Hi everyone, welcome to week ten of
Scientist Chats. We have a very very
special episode for you today, very
special chats. Very- It's one of those
topics that I've been interested in
personally since I was like a kid so
it's gonna be very interesting for me as
well.
Before that just a few of the guidelines
as per usual. Attendees under the age of
13 should be supervised by a parent or
guardian, as well, just to let everyone
know that this session is being recorded.
And for a bit of news, we have one more week of
Scientists Chats before we go on a
little break. It is next week, that's June
24th, so I hope to see everyone there. And
this week our topic is on paleontology,
very interesting. Our guest today is
Ashley Reynolds, who is a PhD candidate in
ecology and evolutionary biology at the
University of Toronto and the Royal
Ontario Museum.
Ashley's research is centered around the
growth dynamics and ecology in living and
extinct cats. So please join me in
welcoming Ashley.
Hello everybody, hope
everybody is having a really excellent
day. I'm just gonna pop up my screen
So...Hello everybody.
So as Adisa said, I'm Ashley and I am a
vertebrate paleontologist. So as a
paleontologist I study animals and
organisms that are extinct. Generally we
study fossils, so that basically anything
that's about ten thousand years old
all the way to hundreds of millions of
years old, and as a vertebrate
paleontology I focus on things that have
a backbone. So you and I, we all have a
backbone, fish have backbones, frogs have
backbones, and all mammals have backbones, so I'm sort of specifically focusing on
all of those mammals. And the reason why
I really like paleontology is because to
me it's sort of- It's a puzzle and I
really like puzzles. But paleontology is
a sort of special kind of puzzle, like
all sciences are a puzzle, like you're
always trying to fit one more piece into
our understanding of how the world works.
The sort of tricky thing about
paleontology, and the reason why I like
it, is because when we're dealing with
stuff that's in the fossil record we
don't actually have all of our puzzle
pieces, we're missing a few of them. So
with a lot of the things we're looking
at, but not all of them, all we have are
bones or the hard parts that are
preserved of them. So if all we have are
bones we can't go out and actually watch
these animals in their natural
environment. So if I was you know maybe
studying Lions today like this lion here,
you know, I would just be able to go out
and watch them and you know maybe I
could learn more about their everyday
lives, what they like to eat, how they
behave,
who talks to who, so you know what is the
social structure of a lion. But with
something that's in the fossil record I
can't go out and look at
so I have to come up with creative ways
to think about how to answer those
questions that we have about anything in
the natural world but in a way that
doesn't require me to actually go out
and look at them like binoculars or
telephoto camera lens. And that's sort of
what got me into paleontology. I actually
I wasn't always into paleontology. I
liked dinosaurs and stuff as a kid, I
think most kids do, but I thought I was
gonna go to school for fashion design. I
actually applied to the fashion design
program at Ryerson. I didn't get in and I
went to U of T instead. So I kind of
spent a couple of years figuring out what
it was that I liked and it turned out
that the courses that I really liked
were the ones where I got to play with
bones and the ones where I got to learn
more about the natural world. So what I
ended up deciding is that that's what I
wanted to do. I wanted to look at bones
and I wanted to learn more about my
favourite group of animals which is cats.
So for my PhD...For my PhD,
which is what I'm working on now, I
started looking at a very special cat to
me and that's this cat here. It's called
Smilodon.
Smilodon is a saber-tooth cat. So what
that means is that instead of having, you
know the nice, or a cone shape ice-cream
cone shaped teeth that cats today have,
like a house cat that you might have in
your house or a lion or a tiger,
saber-tooth cats have these really
long fangs that are squished flat
from side-to-side, maybe sort of like big
steak knives in their mouths which is
really really really cool. So Smilodon is
this special kind of saber-toothed cat,
it's one of many saber-tooth cats. So we
often think of the saber-tooth cat as
being the only saber-toothed cat but
really there's a whole bunch of them. And
saber-cats sort of belong to this
separate group of cats that's different
from all the cats that are alive today.
The saber-tooth cats, none of them are
still alive, they're fully extinct and
what I want to understand is sort of why
they're extinct and what makes them so
different from living cats.
So Smilodon in particular comes from
this time in the past called the
Pleistocene. The Pleistocene was from
about two-and-a-half million years ago
to twelve thousand years ago so quite a
long time ago but not as old as when the
dinosaurs lived. And in sort of common
day language you'll probably hear the
Pleistocene referred to as the Ice
Age and that's because there were all of
these glaciers, these big sort of sheets
of ice that were covering North America
at the time. Now Smilodon is probably the
most famous of the saber-tooth cats and
this is just because we have a lot of
them. They're really famously known from
what are called the Tar Pits in southern
California. But even though we have a lot
of them there's still a lot of questions
we have about how they lived. A lot of
people like to debate about whether they
lived in the sort of big prides just
like a lion does today, or if maybe they
lived alone which is what most cat
species do today. So we have a lot of
sort of conflicting opinions here. Some
researchers will be like, "yeah they were
social," others will be like, "nope
absolutely not they were definitely not
social." So sort of the the crux of what
I'm doing right now is trying to see if
I can figure out whether or not they
were social by looking at something
called life history. And life history is
an area of biology that deals with sort
of the sequence of events that happens
in the life of an organism. So we all go
through these sequences, you know, at one
point we were conceived, then we were
born, then we start to grow up. So you
know you started off as a little baby,
you grew taller, you started to get
bigger.
I stopped growing when I was 5 feet tall
so some of us stopped earlier than
others and some go really late, so that's
where we see these sort of differences
in life history. So you know maybe some
animals are growing longer than others,
maybe some are living longer than others,
maybe for some it takes longer for them
to leave their mother, maybe for some it
takes less time. And these are sort of
the sequences that I think might be able
to tell us about whether or not these
fossils lived in social groups. There's
this idea that if you live in a social
group you're probably going to be
stretching out a lot of these events. So
if you live in a social group you might
stay with your group for longer, you
might take longer to grow just because
there's less pressure to actually get to
a size where you can take care of
yourself very quickly. And this is
something that happens with people. We
actually stay with our parents for quite
a bit longer than most mammals do. But of
course as I was talking about earlier I
can't go out and watch Smilodon in the
wild and I can't see this life history
directly so I have to come up with a
creative way to view them. And the way that I
do this is through something called bone
histology. So histology means the study
of tissues, and tissue is just any sort
of part of your body. So tissue can be
skin, it can be a part of a liver, it can
be pretty much any part of your body. And
histology is actually looking at those
tissues on the microscopic level. So we
take these tissues, we look at them under
a microscope and see what we can see. Of
course bone histology is looking at the
tissues that make up bone. What's really
cool about bone is that because it's
this sort of mix of these cells that
actually lay down the bone and this hard
bone itself, when bone fossilizes we can
still see a lot of these structures. So
we can still see the traces that were
made when the bone was being created
while the animal was alive.
So the
big thing here is that in bone- So in
long bones like a thigh bone or an arm
bone, we get these growth marks that are
formed, and these growth marks are put
down just about once every year. So you
can think of them a lot like tree rings.
Tree rings will grow about once every
year and you can use them to count how
long that tree has been growing. So just
in the same way we can use that for tree
rings, we can count the number of growth
marks in a bone and tell
how long the animal is alive for. And
there are a little bit of complications.
Here you can see in this picture there's
like these little doughnut shapes and
those are... sorry, nope my mouse doesn't
show up over there.
Anyways you can see all these little
donut shapes and you can actually see
them behind me on that, on my virtual
background here. And those actually sort
of cover up all these growth marks as the
animal gets older, so we have to do a
little bit of detective work in order to
count the true age. So this sort of
starts of course by making our
histological thin section, is like we
call them. So you take a bone, you slice
it down the middle there about, and then
you have to grind it really really
really thin. So we have a whole bunch of
specialized equipment in our lab that
helps us make sure that these are so
thin that light is actually going to
pass through them. So what we'll do is
we'll put a thin section sort of on a
microscope, the light comes from the
bottom and as it shines through, it's
actually illuminating all of those
structures that we're looking for. So
here you can see this sort of process
and sequence, and the picture on the
right, you can see those lines that I've
drawn. I've drawn those afterwards, those are
not in the bone themselves or at least
they're not that visible in the bone
itself I should say. And those are those
birthmarks that we're looking for. So you
can see from this there's only two
growth marks. So this animal was probably
not very old. There's a number of other
clues
to tell us that it wasn't very old. You
can see that all holes in the bone,
they're quite big, you can see a lot of
holes you can see through. That means
that this bone was probably still being
developed and that means that this
animal was still growing really really
really fast. So it was at least two years
old and it was still growing pretty fast,
that's a long time for most mammals. So
what we do is we take all these lines
that we've sort of traced and we can do
that for a number of specimens. So we can
take a whole bunch of them and then we
can put them together to sort of look at
how growth happens across multiple
individuals. When we put that together we
get this special thing called a growth
curve. And I know that this is- I promise this is the only graph I'm gonna show you. But
essentially what this shows you is on
the bottom you're seeing how old the
animal is. So you start at birth
at age zero and sort of on the left side
you're seeing how big the animal is. So
of course as the animal gets older it
gets bigger but you can see that at a
certain point the size stops getting
bigger. And what's important here is that
if you're looking at the lion and tiger,
which are the ones in blue, versus
Smilodon, which are the ones in red
orange and green, you can see that
Smilodon is getting bigger than either a
lion or a tiger. So it's going higher up
on that sort of vertical axis but
they're also taking longer to hit that
sort of point where they stop growing
altogether. So what this is, is
essentially the growth is taking a
longer time to sort of stop growing. So
you can think of that sort of like, I
stopped growing when I was 11 and that's
why I'm really short, but you know maybe
someone else stopped growing when they
were 16 and they're 6 feet tall. So
that's sort of what's happening here now,
this is sort of only the first step.
Right now I'm only comparing to a lion
or a tiger and we do know that lions
take a little bit longer to grow than
tigers, and this might be because they
live in these big social groups. We don't
know if that's a pattern that we see
across many animals. So the next thing
that I'm doing is comparing with other
close relatives of cats. The cats belong
to this group of mammals that we call
Feliformia, which essentially just
means their cat shaped. So somebody
looked at mostly their skulls and their
teeth and were like, "ah
these look like cat skulls." And this
includes a whole bunch of different
animals from hyenas, like the spotted
hyena which I know looks a little bit
more like a dog on the outside, but I
promise you they're more closely related
to cats, and includes things like this
bear cat which was the one you see on
the top right, mongooses and meerkats, and
these things called civets.
And if we look at the sort of broader
groups some of them are social and some
of them are not social. So what I'm doing
is sort of like the second part of my
research, is looking at all of these and
seeing if there are patterns, like if all
of the social ones tend to grow a little
bit slower than all the ones that live
by themselves, and try to take that
information and then apply it to what
I'm seeing in the Smilodon. And then just
to sort of take things in a different
direction, because most of what I've been
talking about right now has nothing to
do with Canada but I feel very connected
to to my home, to Canada, I want to talk a
little bit about some of my work
actually finding some of these cool
carnivores in Canada. So what you see
here, this is a photo of me holding a
very special fossil to me. It doesn't
look like much but this is actually one
of the finger bones from Smilodon and it
came from these deposits in Alberta,
so in Medicine Hat, Alberta. I
described this specimen as well as some
other cat specimens all from the
Pleistocene, so all from the Ice Age, last
year, and this is the only specimen that
we have of Smilodon from anywhere in
Canada.
So before we verified that this is what
this was,
we didn't know that we actually had this
really incredible animal here in Canada,
as well. It makes sense that it would be
here but we just didn't have the
evidence for it yet and we're also now
finding that we're getting other really
cool prehistoric animals in Canada as
well. So this one here, this is the lower
jaw, so sort of the bottom jaw right
here of this special kind of wolf called
the dire wolf. And a dire wolf is sort of
like living wolves but they're kind of,
they're more beefy. It's like if a living
wolf worked out a lot. So we have these
really interesting ideas that we
probably have these really cool
Ice Age mammals here in Canada as well.
And what we need to know is sort of how
they got here. We kind of have this
this thought that a lot of Canada was
covered by these glaciers, by the ice
sheets when when the Ice Age was
occurring, so you know under what
conditions could they actually be here.
There were probably only particular
spots that were relatively ice-free
that we could actually find them in and
they might have only been able to be
here during sort of used these times when
the cold and the ice wasn't quite
as bad. So what I've been doing for the
last couple years is very slowly
starting to do my own field work looking
at the Ice Age mammals of Alberta.
So Alberta is really really really
famous for dinosaur fossils and I've
gone out with my supervisor. So you can
see my supervisor David there in the
blue hat, and I've gone with him to dig
up dinosaurs before. But this whole time
there were all of these things I'm
personally more interested in, all of the
mammals sort of sitting above all of the
places that we were finding dinosaurs. So
the last couple years I've been very
lucky to go out and start looking for
more of these Ice Age mammals and start
looking for clues that will help us
figure out sort of how long they were
there for,
if there were sort of patterns of having to
come and go because of the ice. So that
sort of work is where I'm looking to in
the future in addition to looking at
more cats because cats are the best. So
yeah, that's it for me and if anybody has
any questions I'd be really happy to
answer them.
Thank you so much for that presentation.
So the chat will now be- So I have a
question about what was the difference
between paleontology and archaeology?
Very good question!
So paleontology usually deals with
anything that's not human, and
archaeology is looking at sort of the
record of ancient human
civilizations. So there does get to be a
little bit of a gray area there
especially in and sort of the time
period that I'm looking at. So during the
Ice Age you do get a lot of interactions
between ancient humans and the animals
that they lived with. So while I consider
myself a paleontologist, other people
might actually be working on very
similar things but consider themselves
zoo archaeologists. So zoo archaeologists
is somebody that works on the animal
remains that are associated with human
remains. So sort of the key difference
there is that I'm not focusing on
anything that's sort of related to human
deposits.
You never know, there could be human
deposits in the same places that I'm
looking for the animals that I'm
interested in.
Whereas a zoo archaeologist is probably
like, "I found this cool cat while also
digging out humans." There is a little bit
of a gray area as to when archaeology
specifically focusing on humans becomes
paleontology because of course humans
have evolved from apes or we are apes. So
there is definitely some question
at what point you're in the archeology
territory and at what point you're in
the paleontology territory. And I think a
lot of that kind of comes down to
personal choice. Although generally it's
sort of, if you're dealing with Homo
sapiens, so the species that we belong to,
you then, you're definitely in archeology.
Some people who study archeology may
study Neanderthals which are a little
bit more different, but it's sort of- It
gets a little bit hazy there I guess,
So I have a question, some questions coming
in from the chat right now. So you just
showed the little clip of the old image
of the movie ice age. Well the
question is who's your favorite
character from Ice Age?
So I haven't watched Ice Age in a really long time. Which I probably
should watch it more. I
mean I guess if I'm being really biased,
Diego, because he is the saber-tooth
cat.
But yeah I think I have to say Diego.
That's a good one. So keep keeping with
the saber-tooth cat, how did the Smilodon get
his name?
This is a story I really like.
So smilodon means knife teeth. So
essentially when the first Smilodon was
discovered they saw that it had these
really big steak knife like teeth and
they were like, "alright we'll just name
it that!" Now what's really cool is that
of course there are several species of
Smilodon. So Smilodon is the genus name,
so there's three different types
of Smilodon.
The one that I work on is called
Smilodon Fatalis and that means fatal
knife tooth, so it's like extra cool. But
what's sort of more interesting is that
it didn't- It wasn't actually always
called Smilodon Fatalis. When it was
first described somebody called it Trucifelis fatalis, but then they later
figured out that these belonged to the
same sort of group of animals.
And we have this sort of convention in
naming where whoever named something
first,
the oldest name gets priority. So
Smilodon is a name that's older than
true syphilis so now all of those
closely related animals are called
Smilodon.
So I have another question
here. Were there- How many ice ages were
there? Do you know that- Were there more than one?
So that's a very good question. I
guess it kind of depends on how you
define an ice age. So within an ice age,
or at least within the most recent Ice
Age, you get these sort of ebbs and flows
of the ice. So you know the ice will kind
of expand and it'll contract, it'll
expand and it'll contract, but it's still
kind of considered the same Ice Age, it's  just that you have different levels
of iciness during that time. That said
there were times way back in the past
where we did also have a lot of
glaciation or a lot of ice development
in the world. So way way way back there's
this phenomenon that you may have heard
of called "Snowball Earth" and that is
thought of sort of as another Ice Age,
even bigger than the one that existed
during the Pleistocene. And some would
actually argue that we're still in an
ice age, we're just in a long
interglacial period, so we're in a long
relatively warm period of the Ice Age.
We don't really know yet. If we're, you
know, if we're gonna go back to how cold
it was maybe 35,000 years ago but we're
definitely sort of still in a relatively
cold period of Earth's history.
I didn't
know that, thank you for that. So a few
more questions about the Smilodon, about its life history. So how long do you
think Smilodon can live, and what did
they eat?
Both very good questions. So how
long did Smilodon live? The oldest that I
have
record of right now is about 13, which
would make sense. I would say probably
the longest they would live would be in
the 20s, that's about how long big cats
today can live to be. And of course the
tricky thing with knowing how long
something lives, you have to cut up a lot
of them in order to sort of figure out
what the maximum lifespan is. It
also sort of depends on what place
you're getting these specimens from. So
right now I'm not focused as much on how
long they lived, it's sort of more at
what point did they get to sort of
maximum size just because that's a
little bit easier to understand without
being like, I have made thin sections of
every single Smilodon in existence.
I haven't actually. And then the second
part was what did they eat right?
Yeah.
Yeah so there's this really cool
research that I haven't done personally,
but that other Smilodon researchers have
where they look at the ratios of different
isotopes in Smilodon. So different
elements have like carbon, for example
you'll have little carbon molecules, some
which are a little bit heavier than
other ones. And this is because they have
different numbers of the particles that
make up a carbon, and because they're
slightly different in weight, they're
processed by the body slightly
differently. And we can look at the
ratios of the heavy to light elements
and figure out, you know, based on looking
at things that are potential prey, what
that animal might have eaten. So what we
found using this type of analysis is
that Smilodon has these isotope ratios
that are very similar to a lot of sort
of large herbivores that were very
plentiful at the time, so things like
horses, some of the smaller giant ground
sloths. So there used to be some really
really really big giant ground sloths
but there are some that are a little bit
more manageable in size, and Smilodon
probably would have eaten them, and
probably would have eaten the young of
some of those, also some of Smilodon's
close relatives have been found with the
remains of young mammoths and mastodons
they probably ate. So it's likely that
Smilodon would have been able to eat
those as well.
Okay so you mentioned
there being some large animals, like the
larger ground sloths. So one of the
questions you're actually is asking why are
there so many large animals in the Pleistocene era?
Very good question!
So this is something that's sort of
actively being researched. So I guess
less the question of why there's so many
big animals in the Pleistocene as why
are there not so many big animals now? So
we do find that you know- So let's say
after the dinosaurs went extinct or the
non-bird dinosaurs I should say, we
find that mammals started really really
small, but then they rapidly get pretty
big. And once they get pretty big you'll
find that there's a lot of really big
mammals that sort of you know existed
for maybe the last 50 million years. And
the exact mammals that were really big
are different, but you'll find a lot of
mammals that are about the same size
sort of throughout. And then what happens at the end of the Pleistocene is we all of
a sudden see that, especially in places
like North America and Europe, all of the
really big mammals or most of the really
big mammals all go extinct at once. And
there's a few reasons why that might be.
It could be because climate was changing
pretty quickly so we were going from
this relative cool period to a slightly
warmer period, and it could also be
because humans were starting to move
around the world and they might have
been hunting mammals to extinction, and
sort of outcompeting
the predators that we have hunted the
same mammals. Now we don't have an answer
yet as to which one of those causes is
sort of the predominant one. It depends a
little bit on where you are in the world.
So in islands like Australia or
Madagascar, we have pretty good evidence
that humans are the main cause, in other
places it may be a combination of humans
and climate change, or it may be
different for different species. So some
species may have been more susceptible
to the climate whereas others may be
more susceptible to the hunting or
competition from humans.
Okay so with that, what
sort of climate did the Smilodons live in?
A little bit sort of like a grassland. So
if you think of the prairies today, they
probably lived in a lot of those areas.
It seemed like they liked areas where
there was a lot of grass, so relatively
open areas, but enough cover for them to
be able to stalk their prey. So Smilodon
is not as well developed for running as
some other saber-tooth cats are or as
some living cats are. They're very
similar in proportion to a jaguar, and
jaguars live in sort of more heavily
covered areas. Now Smilodon we don't
think that necessarily meant that they
were living in these sort of like dense
forests just because of other evidence
that we found with them. Things like
horses don't generally live in dense
forests and we find a lot of horses
where we find Smilodon. In this case
they're probably that big and stocky
because they required all that power to
bring down their very big prey. But some
of the good things that we found, an
association like pollen or again
these isotopes suggest that they were
probably living in sort of these mixed
areas, so sort of grasslands with a
little bit of forest cover.
So if they
were built the way you described them
what is the need for them for the
massive teeth?
So I guess it's sort of more of a
question of which came first. So it turns
out that you get this sort of very, this
evolution of these massive teeth right
along with this change in proportions. So
it's thought that those massive teeth
are the main things that help you kill
your prey. So if you think of having a
steak knife it cuts a lot more
effectively than a butter knife does or
an ice cream cone would. So the way that
living cats hunt, or living big cats I
should say, is that they usually
don't actually cut into the prey at all,
they'll sort of grab on to something
like a throat, and they usually wait for
the animal to suffocate because it can't
breath. Now with something like a big
steak knife what you're probably going
to be doing is you're probably going to
be kind of taking a really big bite and
causing potentially suffocation because
you're cutting into the airway, but also
a lot of bleeding. And as we all know
bleeding is not very good and we don't
want to do it because you can die if you
bleed too much. So it's thought that these
big teeth were probably made to to sort
of cause this really huge damage to the
animals that would have made them die
very quickly. Now of course if you have
these long flat teeth they're actually
much more prone to breaking than the
teeth in living cats. They're sort of,
because they're flat from side to side,
if they get snapped to the side, they just
snap. So that's where those really big
and strong proportions come in because
if you're going to use those really
fragile teeth you want to make sure that
your prey is not struggling too much so
they're not going to snap your teeth, and
those really strong forelimbs will help
you kind of
hold them down and make sure they're not moving.
So would you say with that, one the  question actually asks here,
is Smilodon built to pounce or jump
really high, or they built more to wrestle?
Probably built a little bit more to
wrestle. I'd say they probably are able to
jump pretty well not necessarily any
better or worse than most cats of
similar size. Usually the bigger you get
the harder it is to sort of like get as
much air on a jump. So Smilodon, its
back legs, which would be what power a
jump are relatively similar or more
similar to what we would see in a living
cat than their forelegs are. So they're
probably about the same as like the lion
or tiger. But we do know from some of the
injuries that we found in fossil
Smilodon that a lot of the injuries we
find are probably from wrestling with
prey. because they were probably grabbing
on to them and then if the prey is
struggling you get a lot of a lot of
pressure that's put on the spine. So we
find a lot of injuries in the spine of
Smilodon and that suggests that they
were doing a lot of that wrestling.
Okay,
I have a question here about, does the
fossil record in Alberta, in the Alberta
province provide evidence that Smilodon
arrived to North America via Beringia?
Very good question.
So it doesn't provide evidence that
Smilodon came from Beringia.
So Beringia, for anybody who might not
have heard of it before, is essentially
this big land bridge that connected
eastern Asia with the sort of western or
northwestern tip of North America.
So back during the Ice Age, this big
land bridge that animals could cross
from Asia to North America and
we do know that Smilodon was already in
North America before the species that I
looked at existed. So the sort of
ancestor to Smilodon Fatalis, the one
that I work on and the one that I found
in Alberta, is called Smilodon Gracilis
and it's most commonly found in southern
North America, so it probably evolved
there. So we had all of these saber-tooth
cats in North America for quite a long
time before Smilodon existed. But
Alberta might be able to provide
evidence that some of the species of
other cats that we know may have been
coming into North America from Beringia.
So in North America we also had two
species of lion. So we had the American
lion, which is the one that's found at
the La Brea Tar Pits in Los Angeles. It
was a really really big cat who's even
bigger than Smilodon so it was like
twice the size of a living lion, they're
huge. But we also had in Eurasia what's
called a cave lion, and the cave lion is
found in places like Alaska and Yukon
Territory. Now we have some evidence, but
not conclusive evidence, that we might
have found cave lions and Alberta as
well. So if we were finding cave lions in
Alberta, those were probably coming over
from Beringia, and they were probably
coming down this little corridor where
there was no ice sort of right through
the center of Alberta. I don't know yet
if that was definitely the case. All we
have is a bone where it looks a little
bit more similar to a cave lion but we
don't know if that's just because
different individuals look a little bit
different or if it's actually because
the two species look different. So we
still need to do more research there but
it's possible that some animals were
actually coming down through there.
So, and just again, Beringia 
is that Bering Land Bridge, correct?
Yeah. There's the Bering Land Bridge.
And then the area we call Beringia.
Okay thank you for that question.
That was a very good question.
So I have another question here about
whether they Smilodon would have
camouflaged in tall grasses, and what
colour were they?
Also a very good question.
Soo we don't actually know what
colour they were because we don't have
any that are preserved with fur. We can
make some guesses about what colour they
might have been based on the colours we
see in other cats. So most cats that are
alive today are either spotted or
straight, of course there are some
exceptions to this. So cougars and lions,
when they're adults, they're sort of just
this brownish colour. So it's possible in
most of the these sort of illustrations
you'll see a Smilodon usually have a
 lion like colour. So sort of this
monotone, sort of brown colour. But the truth
is we don't actually know that. From some
of the environment data that we do have
it's possibly more likely that they
would have been spotted or striped just
because they would have wanted to use
that for camouflage maybe, not as sort of
heavily spotted as like a jaguar or a
leopard, but some good spotting. The truth
is we don't really have a good grasp on
sort of the reasons why there are all
these different patterns and how they
relate to the environment, and we also
don't really know enough about the
environment that Smilodon lived in to
be able to say. It's also possible that
Smilodon lived in a whole bunch of
different environments. We can't rule
that out. A lot of cats do that as well.
So the truth is we don't know, so that's
one of the fun things that when we get
our friends who are paleo artists to
reconstruct these animals for us, that's
where they get to really sort of do
things that they find interesting but
within sort of the realms of reality.
Okay so a lot- So is it that, it's not
that they're taking artistic liberties,
just we're doing it based on the
best scientific knowledge that we have.
Yeah exactly. So you know when I was I
have been working with a friend she was
is doing a reconstruction for an
upcoming paper and you know essentially
what I told her is what I just told you
like I think actually the most likely
are probably going to be some sort of
spot or stripe, but not as extreme as
like a clouded leopard or a jaguar. So
I'm giving these sort of restrictions
that make it as scientifically accurate
as I can make it, but then you know
within that, because we don't know, it's a
place where you can have a little bit of
fun with it.
Alright, very interesting. A few more questions here.
You mentioned one of the reasons like
some of the cats have like thicker
bones is because of their age. Is
it usually bigger cats that would have
beefier bones? Based on the previous question, do bigger cats
have beefier bones or would you see okay
something is older would tend to have
those larger denser bones?
That's a very
good question. So what happens is you'll
get- These bones will sort of grow bigger.
So like if it starts really small like
this, it will kind of go [moves hands] to a
certain point. And then while the animal
gets older, at least with with mammals,
you'll get these, sort of rings will get
deposited, but they won't put a lot of
circumference on it. So this creates this
sort of area on the edge of the bone,
which is, you can call an outer
circumferential layer. So it's this layer
where you have all of these growth marks
that are all squished together on the
edge of the bone. So in that case the
animal is not really getting any wider
in its bones. What's interesting is that
while many animals, the inside of the
bone will also sort of get bigger. With
Smilodon, I have some evidence but I
don't know for sure yet, that suggests
that a sort of hollow area in the
middle of the bone, it's called a
medullary cavity, it looks like
might actually get smaller as Smilodon
gets older. So that might be a way for it
to sort of help strengthen its bones
without sort of making them so wide that
they don't really perform well for what
they're really designed to do, which is to is
hold of the body. Now that's sort of
early days, I don't know that the real
answer to that yeah that's just
something I've noticed in the specimens
that I've worked on.
And so since.... Because
your work is based- You do a lot of work
at the [Royal Ontario Museum], correct?
Yeah
Is it that that's what your lab is?
Yes.
Okay, so
because of that, and because of what's
happening with quarantine and Coronavirus and all that, how has that affected
your type of research where you need to
physically be there looking at samples?
Yeah I mean it's affected it quite
a bit.
So right now what I'm working on is I'm
working more on what I was talking about at
the sort of end of my presentation. So
doing that work of looking at what other
close relatives of cats are doing. So I'm
lucky enough that all of the data I
needed for that had all of the
information I needed, or most of it I
should say, not all of it, I already had
before we started quarantine. So right
now I have to sort of focus on that one
piece of information. I'm not really
working on my histology work right now
because I still had a lot of thin
sections that I had to make. There is
some work that I can do. So I do have
some images that I have available to me.
So I can do things like you know tracing
those growth marks to see how big they
are, and then I'm also working on
publishing some of the papers that I
maybe have a kind of chance to work on.
So right now I'm working on a paper
about Smilodon from Ecuador and
working on that sort of that direwolf
that I showed you, working on it with a
good friend and lab mate, Talia, who's helping
me make that project more cool and science-y.
And one final question.
How did you get- I know you spoke about
how you got into that type of work, but I
want you to just elaborate a little bit
more. How did you really get into that,
how would you advise someone who's
interesting in this type of work? 
What steps to take on average to get
into that type of paleontology that you
do?
Yeah, so for paleontology specifically,
paleontology is sort of a cool union of
two disciplines. So it's biology plus
geology. Because a lot of what working
with in the fossil record, they're all
found in rocks and we get a lot of
information about where the animals we
study come from from the rocks that
they're actually buried in. So what I did
was when I was in university, once I sort
of figured out that this is what I
wanted to do, which I didn't know right
away, I started taking courses that were
both biology related and talked about
all of the diversity of life that we
have here on Earth, as well as some
geology courses just to get a little bit
of an understanding about, you know, how
Earth works, how it how it moves, things
like that. We do get people who come in
paleontology from different areas.
Some people are much more biology
focused which I was, whereas other people
were much more geology focused. And it
sort of depends on the school that you
go to. So some schools if they have a
paleontology program, which not all do,
the paleontology program is usually
either in the biology department or it's
in the geology department. So usually
it's sort of what you're most trained in
depends on where you're going. Here at U
of T I'm getting my degree in ecology
and evolutionary biology so I'm much
more biology focused now. For sort of any
science degree, any science, like even if you
don't want to be a researcher. Basically
any sort of area in science, of course
the things to focus on or whatever type
of science you're interested in whether
it's chemistry, physics,
or biology, more and more even in
paleontology, we are doing math. And I, you
know, math wasn't my favourite thing. I
find it very interesting to think about
how the math that you're learning can
help you answer questions that you're
interested in because I, yeah I didn't
really like math until I started
applying them to the questions, until I
figured out that I can use it to answer
these questions I had about the natural
world. And then if you know doing
something like research is something
that someone's interested in, I actually
do recommend sort of learning how to write, and making sure to actively
write. One thing we don't talk about is
that one of the biggest parts of what we
do is sharing our research, either with
the public like I'm doing right now, so
with you know everybody, but also just
with other scientists. And that means
that we actually do have to do a lot of
writing. So sort of working on those
writing skills can really help and yet
that doesn't even need to be science
writing. Creative writing helps a lot. It
helps you learn sort of the ways to
make sentences sound good and things
like that. So those are sort of the
things that I would focus on but mostly
just always make sure that you're doing
something that you find fun, and don't
always restrict yourself to just those
things. I think more and more we're
seeing that scientists are becoming
well-rounded and we're trying to learn
things about history and sociology and
stuff like that. So yeah I guess my
terrible answer is do everything, but
mostly it's just stay curious, and just
yeah stay curious and ask, always ask
questions about the world around you.
Very good answer.
I like how you emphasize on the writing
and math because
I think people take those skills for
granted sometimes. What am I going to use math for?
And I think a lot of the time we
sort of, I don't want to say forget,
but it can be hard when you're learning
math because you learn it in a very
technical way. It's hard to learn about
the applications. So it was definitely
something that I did when I was younger
is I sort of slacked off in math or
didn't like it as much because I didn't
see the way that it would be sort of
helpful, or the way that it could help me
learn about other things.
Okay I have one
more question. This is a question for
myself. So I don't know if you grew up watching
Power Rangers. They would say saber-tooth
tiger, right. mm-hmm
And so the correct name is saber-tooth cat,
it's not a saber-tooth tiger.
Yeah so I mean
whatever words you use to help you get
across what you mean is fine. The reason
why I say saber-tooth cat is because of
what I was talking about earlier, where
saber-toothed cats are all sort of in
this different group of cats from
living ones. So when we say saber-toothed
tigers, some people think that it's very
closely related to a tiger. But a
saber-tooth cat like Smilodon
is just as closely related to a tiger as
it is to house cat. So that's why I
prefer to say saber-tooth cat. I have
no problems with other people saying
saber-toothed tiger. I know that that's
sort of the most common way to say it,
but I just feel like because I work on
them I want to be a little bit more
precise in the words that I use.
Okay, do you have any final words for everyone
listening here today?
I just I want to say
thank you all for coming.
this is very very very fun. Thank you for
all of your great questions.
I really enjoyed answering them. And make
sure that you're always staying curious
and always learning more about the natural world.
Perfect thank you everyone
for joining us have a great day thank you.
Thanks everyone.
Thanks very much Ashley!
Oh, no problem!
