[♩INTRO] You might sometimes venture outside your culinary
comfort zone. Maybe you’ve eaten toasted crickets, or
you’ve sampled escargot on a trip to France. But the seven organisms on this list don’t
just dabble in out-of-the-box delicacies, they make some really bizarre dietary choices. Like, you just don’t expect sharks to eat
plants, or, well, anything to live on a diet of dead
turtle shells. But apparently, having an adventurous palate
has its advantages, evolutionarily speaking. There are at least 13 species of crocs and
alligators in the order crocodilia that eat fruit, for
example. These unexpected frugivores include infamous
predators like the American crocodile, Nile crocodile
and Saltwater crocodile. But by far the best studied is American alligator. They’re known to consume basically anything
meaty, including adorable little dogs that venture
too close to bodies of freshwater in the southeastern US. But they also eat a huge range of fruit, nuts,
seeds and other plants at least 34 different species. And no one is really sure why. The leading theory is that they’re just
generalist feeders, so they eat whatever’s available. But some biologists think they seek out nuts
as gastroliths: stones that are swallowed to aid digestion. You see, crocs and gators have pretty rude
table manners and do not chew their food. They swallow it whole and leave the work to
their gizzard: a thickly walled portion of the stomach that
grinds up food. Having something hard in there can help break
down tougher chunks of meat. There are also some that think all this fruit
and nut eating is purely accidental. But... there have been sightings by locals
of gators plucking kumquats right off a tree. And in 1871, a French naturalist noted Mexican crocodiles are so fond of avocados that some people started calling the fruits
“alligator pears”. So it seems unlikely that all this fruit-eating
is unintentional. The bonnethead shark is a small member of
the hammerhead family, and like its relatives, its usual diet consists
of shrimps, molluscs and crabs. But it also likes to supplement that protein
with a nice salad of seagrass. In fact, stomach content analysis has shown
that seagrass can make up as much as 62% of the shark’s
diet. At first, scientists thought the sharks were
eating all that grass by accident because juvenile sharks seemed to be eating
more of grass than adults. They thought the young sharks were just clumsily
chomping on some grass as they learned to hunt. But a study presented at the 2018 Society
for Integrative and Comparative Biology conference tells a different story. When sharks were kept in a tank and fed a
diet consisting of 90% seagrass and 10% meat, they all gained
weight. And tracers put in the grass were found in
the sharks’ blood, revealing that they’d actually absorbed
nutrients from the grass. The researchers think an enzyme called b-glucosidase in the sharks’ stomachs might be helping
them break down the fibrous cellulose in the plants. This enzyme is also found in the guts of seaweed
eating fish and three species of plankton eating sharks. But it’s never before been found in a species scientists thought was a meat eater. The sharks probably can’t survive on a purely
vegetarian diet, but they seem to be more omnivorous than scientists
originally thought. In France, escargots, or snails, are a luxurious
treat. It turns out there’s a group of snakes that
also likes to indulge in this slippery delicacy. The family Dipsadini (otherwise known as the
“goo-eating” snakes) contains almost 80 species. Some eat snails and slugs as a side dish, while others are totally molluscivorous, meaning feed exclusively on snails and their
kin. And they have special adaptations to cope
with such slimy meals. Almost all of the dedicated snail-eaters have
a lot of loose, folded skin on the base of their mouths and
teeth that curve backward. These allows them to clamp down on the snail
shell and squeeze much of their lower jaw into it. Then, with a few jerky movements, they slurp
the snail out. Many also have enlarged infralabial glands
in the floor of their mouths which secrete a protein-rich fluid out of
holes near the front of the lower jaw. Scientists think this is comprised of toxins
that immobilize the snakes’ prey, or help loosen snails from their shells, though
no one is entirely sure. Snails might seem like a strange diet choice
for a snake, but biologists think it evolved because of
competition. By scaling trees and feeding on less popular
fare, these snakes were able to carve out a niche
for themselves. The Indian Grey Mongoose is a ferocious little
carnivore with a protein-heavy diet of eggs, insects,
frogs, scorpions, crabs and fish. But it also has quite the sweet tooth. Camera trap footage from 2015 caught this
meat-eater slinking up to sugarbush flowers and drinking
their nectar. And that’s just not something carnivores
usually do. If they vary their fleshy diet, it’s with
fruit, not nectar. So the scientists were really surprised to see these furry meat-eaters downing nectar. The flowers do have a bit of a cheese-like
smell, so it’s possible the animals were initially
drawn to what smelled like carbs or protein. But the researchers think they return for
the sugar rush and the nectar certainly has no shortage of
that. It’s about 30% sugar by weight. It seems a few slurps and these guys were
hooked. For one of the species of sugarbush observed, the mongooses accounted for a little less
than half of all visits recorded. They were even seen carefully pushing leaves
aside to gain access to that sweet juice. And after the mongooses had their fill, they
left with snouts covered in pollen, which made researchers think they could be
acting as pollinators although that’s a hypothesis that needs
further testing. Tineidae moth caterpillars are notorious for
eating sweaters. But one species munches on something much
creepier than your clothes: he shells of dead gopher tortoises. Ceratophaga vicinella belongs to a sub-group
of Tineidae moths that feed on the protein keratin, usually
from things like horns, hooves, or hair. You can spot them by looking for hard, brown
tubes these are called larval casings, and they’re
how the caterpillars protect themselves. In 2005, researchers in southern Florida noticed
similar casings on the shells of dead gopher tortoises and concluded that the shells were the main
food source of a new species. But why the super restrictive and, let’s
be honest, somewhat disturbing, diet? Well, all moths need to eat protein so they
can spin their cocoons. They could eat leaves or your sweaters for
their protein fix, but keratin is everywhere, if you have the
tools to digest it. These moths have super acidic stomachs and 29 different kinds of protein-breaking
enzymes called proteases sloshing around in their guts. And since no other moths in the area digest
tortoise shells, they’ve got an exclusive ticket to an abundant
food source. Or, what was an abundant food source. The only problem though with being such a
picky eater is that you’re in trouble if your food disappears and that’s exactly what’s happening. Gopher tortoises are declining due to habitat
loss, being squashed by cars, poaching and disease. And if the tortoises disappear, so too will
this strange little moth with its weird diet. Pitcher plants are carnivorous plants that
usually feast on bugs and such that they lure to their funnels using attractive
scents. At the bottom of that funnel is an acidic
digesting pool which does exactly what it sounds like it
does. But the Raffles' pitcher plant found in the
jungles of Borneo doesn’t just eat insects. It also eats guano. Yes... bat poop. Raffles’ pitchers actually come in five
growth forms one of which, called elongata, grows high
up in the trees. Because of its long, slender shape, fewer
insect-attracting compounds, and low levels of digestive fluid, it’s
not actually very good at trapping insects. Its insect capture rates are about 7 times
lower than other varieties of the same species. What elongata varieties are good at, though,
is acting as a nice little hotel for woolly bats. Their narrower shape and lower digestive pool
mean the bats can snuggle up in the pitchers during the day
to stay safe from predators and the elements. And the plants don’t mind this intrusion
because the bats’ provide them with nitrogen through their guano and urine. Yummy! As gross as that might sound, the pitchers can get about 39% of their nitrogen
needs from the bats’ waste enough to balance the fact that they don’t
catch as many insects. So this bat-pitcher plant relationship is
a nice example of mutualism, where both parties benefit from a particular
interaction. Imagine it’s the middle of the night in
the forests of Madagascar, and you’re a bird peacefully trying to get
a little sleep. While you dream of tasty grubs, you might unwittingly become the target of
the Madagascar tear drinking moth. This 26 millimeter-long moth lands near a
bird’s eye and jabs its sharp, 10 millimeter long, barbed
proboscis under the unsuspecting bird’s eyelid. It then proceeds to slurp tears right out
of the tear duct a feeding style known as lachryphagy. It’s not weird that they crave such a salty
beverage. Lots of butterflies and moths engage in what’s
called puddling, where they take sips of muddy puddles or other
moist things like rotting fruit to get a boost of nutrients
and fluid. But for Madagascar tear drinking moths, tears
aren’t a treat they’re a complete meal packed with all
the protein and minerals they need. And because the tears are the main component
of the moth’s diet, scientists have labelled them ophthalmotropic
moths. There are other tear drinkers, too, but they
usually go for large mammals or reptiles the Madagascan moth is the only one to feed
on birds. Stealing from an animal that could kick or
bite at you might seem risky, but biologists think it may actually be safer
than regular puddling. That’s because it’s unlikely the moth’s
usual predators want to risk waking a sleeping giant. And for what it’s worth, the birds don’t
actually seem to feel anything. Some biologists wonder if the moths inject
an anaesthetic when they stab their mouthparts in, but so far, no one has looked to see. These diets might seem bizarre, or even gross, but they all offer the species on our list
something useful. Whether that’s a way to survive stiff competition,
get extra nutrients, or make up for bad hunting skills, they show that diversifying your meals can
be a winning strategy. And hey, we all love a little variety in our
diets, so why shouldn’t an alligator eat a kumquat? Thanks for watching this episode of SciShow! If you think these animals have some unexpected
meals, you should see which species made our list
of vegetarian animals that actually eat meat. [♩OUTRO]
