The glowing creatures hidden in your backyard
[Music]
meet the loose shot dragon fish
an animal that is adapted to living
thousands of meters below the ocean’s
surface in the deep sea
in this environment darkness is so
pervasive that often the only light that
animals can see
is that generated through
bioluminescence through living organisms
blue bioluminescent light travels the
farthest in water
and over millions of years of evolution
many animals have actually lost the
ability to see the color red
but take a look at this loose jaw dragon
fish do you see the large red organ
under its eye
this particular fish is capable of
emitting a red light that acts as a
private flashlight that only it can see
while other animals are busy being
distracted by the brilliant blue flashes
of light happening all around them in
this deep sea habitat
the loose jaw dragonfish can hunt
sneakily undetected
it is an extraordinary example of an
animal using light and color
to thrive in an environment that often
feels alien to us
we’re often fascinated by glowing life
forms
in science fiction films like star wars
and avatar
but the reality is that animals right
here on earth are capable of glowing via
biofluorescence
and bioluminescence scientists recently
discovered
the many sharks rays and other marine
fishes particularly found in coral reef
habitats
are capable of biofluorescence
biofluorescence occurs when an organism
can absorb light of one color such as
blue
and re-emit that light in other colors
such as vivid greens oranges and reds
even dory from finding nemo was found to
be hiding this hidden visual phenomenon
now we know that biofluorescence is
widespread among cartilaginous and
ray-finned fishes
but the extent to which it’s been
documented in terrestrial vertebrates on
land
has comparatively remained a mystery
that seems odd right
speaking as a member of a terrestrial
vertebrate species
shouldn’t we know this by now well often
our understanding of the world is
limited at least initially by our own
perception
our senses as humans have been shaped by
our own evolutionary history
but the senses of other animals have
been shaped by
different environmental pressures so
they may see the world
in a completely different way so how do
we break through our assumptions that
may limit our understanding about the
natural world
well today we’re going to be shining a
new light on amphibians
and we guarantee you’ll leave here
seeing them in a completely different
way
i’m a herpetologist someone who studies
amphibians and reptiles
and i’m particularly interested in how
amphibians interact with one another
and how they interact with other animals
in their environment
and i’m an ichthyologist a scientist
that studies fishes
i’m interested in deep sea fishes in
their adaptations including
bioluminescence and biofluorescence
when matt and i first met i was setting
up my new lab spaces at saint cloud
state university
and we got to chatting about our
interests including matt’s work with
biofluorescence
in fishes we quickly realized that
neither of us knew anything about
biofluorescence
in amphibians there are more than 8 000
species of amphibians worldwide
from frogs to salamanders to the
odd-looking
legless sicilians that live in the
tropics it was
amazing to realize that we didn’t know
this about them already
but we knew we wanted to find out to get
started we made a setup in the lab and
the field
to explore for the presence of
biofluorescence among amphibians
in the field this essentially meant we
were running around with a fancy blue
flashlight
and some awesome yellow glasses the
flashlight acted as our light source
and the glasses acted as a filter so we
could better visualize the fluorescent
emissions coming back from these
amphibians
while in nature many animals have
evolved over millions of years to have
eye specializations to potentially see
these fluorescent emissions including
maybe built-in filters
for us scientists we have to wear shades
what we found amazed us
so one of the first species that we
looked at
was this eastern tiger salamander
under our blue lights and through our
filter
the salamander’s yellow markings shown a
brilliant fluorescent green and we were
really taken aback
by how bright this biofluorescence was
we wanted to understand how widespread
this phenomenon was across
amphibians and whether it varied from
species to species
getting a sense of this would let us
know how early on in the evolution of
amphibians this feature may have evolved
and also as potential importance for
their biology
initially we focused on salamanders so
salamander biodiversity is highest in
north america
with every species of salamander we
tested we discovered new patterns and
colors that scientists
had previously not seen humans had
literally never seen
a salamander like this before
and we wondered if this kind of
biofluorescence is present
and variable in salamanders is it
present and variable in
frogs or what about in those odd legless
sicilians in the tropics
it turns out that every species we
tested was capable of biofluorescence
so now that we know that amphibians can
glow one of the big questions is why
well we know from fishes that they can
either produce and emit light or absorb
and re-emit light for a variety of
different functions
if we look back at our loose jaw dragon
fish that we started with
they actually use a combination of
bioluminescence and biofluorescence to
emit that red light that they use to
hunt prey items undetected
in this example of a barbell dragonfish
they use glowing
from their chin barbell to attract prey
items and they also use glowing from
their ventral surface and they’re along
their belly
to hide their silhouette as they make
daily vertical migrations to and from
the ocean’s surface
finally in this example of a lanternfish
they use their ability to glow
in their dark deep-sea environment for
communication
including for reproductive displays
now it’s possible that the function for
amphibians
can also vary by species to species or
in some cases there may be no function
at all
we now know that many frogs are highly
specialized to see the color green
including in the wavelengths that we
observed our fluorescent emission
patterns in
also many amphibians are highly active
in environmental conditions that are
conducive to biofluorescence
including at night under moonlight
now some plants and fungi biofluoresce
as well but the colors vary from red to
green
if an amphibian’s color pattern can
match that of its background
while it’s fluorescing then perhaps
biofluorescence serves as a kind of
camouflage to help them hide in these
habitats
this is one hypothesis for why fishes
living in coral reefs will biofluoresce
another idea is that maybe amphibians
use these bright colors to help
find and choose a mate we’ve started to
learn that many of the colors and
patterns that vary
between males and females actually
fluoresce really brightly
in fact in some salamanders specific
parts of their reproductive anatomy
shine a bright brilliant green almost
like a beacon to help them
find each other in the amphibian version
of a nightclub or a rave
some amphibians use color and pattern to
warn potential predators that they’re
toxic
in our study we found that many of these
warning patterns were also highly
fluorescent and they shine with a bright
green intensity
interestingly enough a number of
predators of amphibians such as birds
are well known to be able to visualize
ultraviolet and fluorescent emissions
it’s possible that these fluorescent
displays associated with these color
patterns may also be aiding and telling
these predators that these organisms are
toxic
now we don’t fully understand yet how
all of these amphibians biofluoresce
it could be that pigments in their skin
or compounds and their mucus
are responsible for the glow scientists
have discovered that jellyfishes and
some marine fishes
produce a protein that’s responsible for
biofluorescence
in those species and it may be that
amphibians produce a similar kind of
protein
or perhaps their biofluorescein in a
completely different way
we also hope that this discovery will
help us better find
amphibians in their natural habitat many
amphibians can be cryptically
camouflaged or difficult to identify in
their environment
biodiversity surveys are critical for
identifying threatened endangered
species
and unfortunately one in three amphibian
species is currently in decline
threatened or endangered we hope that
now that we know that they glow
we could maybe better find document and
save these animals in the wild
collaborating on this work has let us
see
amphibians in a totally new light and
we’re curious to learn more
we hope that we’re leaving you with a
similar sense of
awe and intrigue about these familiar
animals
our work serves as a kind of road map
for future studies
interested in understanding the biology
of amphibians
and the really exciting reality is that
there’s still so much more left to learn
sometimes we take the biodiversity
around us for granted
and dream about distant wonders and
galaxies far away
but the reality is one doesn’t have to
look any farther than their own backyard
to discover an entire hidden world of
glowing life
just don’t forget your special lights
and glasses
thank you thank you
you