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