The monkey with the enormous hooter
Proboscis monkeys are aptly-named. Their big noses look ridiculous to human eyes, but other proboscis monkeys may think otherwise. It's been suggested that having a big nose might help a male to attract females, much as a peacock's colourful tail does.
Having a big nose may also allow a male to make louder honks, warning off rivals.
Beyond their whopping noses, proboscis monkeys have another distinction. They may be the only primate species that chews the cud, regurgitating food for a second chew just like a cow.
Ostrich sex is unusually brief
Male ostriches are one of the few birds that have penises, but they don't have particularly good ones.
Human penises are inflated with blood, which is under high pressure. This allows a human penis to remain erect for many minutes.
For some reason, ostriches' distant ancestors went for a different system. They inflate their penises using lymphatic fluid, which is under much lower pressure. As a result, they can only maintain an erection for a few seconds.
The improvised claws of the hairy frog
Hailing from Cameroon, the hairy frog has a secret weapon. Its back feet have extendable claws, a bit like those of a cat.
But these claws don't work like those of your domestic moggy. They are made of bone and are part of the frog's toes. When it feels threatened, it breaks the bones and pushes the claws out through its skin.
In fact the frog is more similar to Wolverine from the X-Men, if Wolverine could extend his adamantium claws from his feet.
The leggiest animal of all
Despite their name, no millipede has 1000 legs. The species that comes closest is Illacme plenipes, which has more legs than any other known animal.
Females of the species can have up to 750 legs. Nobody knows why: it might be that I. plenipes has evolved a really long gut to get the most out of its food, and the legs are simply a by-product.
It is only found in a 4.5 sq km area of California, the precise location of which has been kept secret for the animals' protection.
Toads have moustaches
Each male Emei moustache toad has a sharpened moustache, which it uses to fight other moustachioed males for territory.
The moustaches aren't made of hair, which amphibians don't have, but from solid spines growing out of the toad's upper lip. Each toad attempts to ram its moustache into its opponent's belly, puncturing it.
And so do spiders
The brown huntsman spider also grows impressive facial fluff.
It's not just for show: this spider uses its moustache to hunt. The white hairs stand out in the dark of night and help it attract prey.
Bats give oral sex
In the privacy and dark of the night, within little tents fashioned from palm leaves, there are small furry animals that like nothing better than to indulge in bouts of oral sex.
More specifically, in China there are fruit bats that engage in fellatio with one another. During sex, female short-nosed fruit bats will bend to lick the base of the male's penis, stimulating it to prolong rather than shorten the copulation.
Though humans regularly engage in oral sex, few animals are known to do so. Bonobos occasionally dabble in fellatio, but that tends to be between young males, who do it for play rather than sex.
Seals have sex with penguins
So ridiculous it made global headlines, when first reported in 2008. And then again in 2014, when the act was caught on camera. No one really knows why the seals do it, and the penguins do not seem to be willing partners. Indeed, one penguin was promptly eaten after being assaulted this way.
Penguins cannot taste fish
More bad news for penguins. Despite fish being their main source of food, research shows they cannot actually taste it.
A study published in February 2015 discovered that they have lost the ability to taste fish. They only have the genes to make receptors for sour and salty food.
Apparently, because penguins tend to swallow fish whole, it doesn't really matter whether they can taste it or not.
Crazy cows like weed
Cows are partial to drugs. In the US and Mexico, they eat locoweeds: poisonous plants in the genera Astragalus and Oxytropis that grow in their fields.
They become lonesome, start walking funny, and bump into things. Eventually, they get so high they will take huge leaps over the smallest obstacles, such as a stick.
Dolphins get high on pufferfish
Some dolphins are also prone to a bit of recreational drug use.
Pufferfish are toxic, but in small doses the neurotoxin they release seems to have a narcotic effect. Dolphins have been reported playing with pufferfish and apparently getting high .
This behaviour was captured by the BBC's Spy in the Pod programme. It is the first reported case of "drug use" among bottlenose dolphins.
Dracula ants suck babies' blood
Sucking the blood of another is weird. Sucking the blood of your own offspring is weirder still.
But that's what Dracula ants do. They chew into the bodies of their young and sucking out their haemolymph (the insect equivalent of blood). The process is called "non-destructive cannibalism", and on the surface it seems to run counter to the laws of evolutionary biology. Parents don't normally feed on their own young.
Dracula ants were discovered in 2014, living in a rotting log in Madagascar. Their young, by the way, don't end up dead: just full of holes.
Animals with multi-functional anuses
One species of sea cucumber, Parastichopus tremulus, has a wonderfully multifunctional anus. Not only does it defecate through its anal opening, it breathes through it too.
Sea cucumbers also use their bottoms for defense. When challenged by a fish or crab, they will face away from their attacker and contract their muscles, ripping their guts apart and widening their anus. They then expel some of their guts, leaving them dangling outside of their body. Some species even expel their respiratory organs through their anuses.
This isn't for show. Sea cucumbers can actually wrap the attacker up in a bundle of their innards, allowing them to crawl away safely. They regrow their insides later.
Penguins' projectile poo
While we're on the subject of anuses, penguins have a special power. No, not the ability to endure months of freezing Antarctic conditions, nor their talent for swimming underwater, or the secret technique they use to get airborne. Penguins are prime pooers.
In 2003, scientists showed that penguins poo with between five and ten times the force a human does, a discovery that won an Ig Nobel award.
They do it to avoid soiling their nests. This way they can shoot their poo out over the side, without bothering to move.
Turtles' dirty mouths
And if that excretory effort isn't enough, Chinese soft-shelled turtles wee through their mouths. When one of these turtles needs to urinate, it goes in search of a puddle, and dunks its head under the surface.
It then pees, passing urea across tiny, finger-shaped protrusions within its mouth.
These structures are usually used for breathing underwater, helping to exchange oxygen and carbon dioxide. But the turtles have co-opted them to pass urea. Their toilet habits appear to be unique.
Male scorpionflies have anal horns
Courtship can be a long and arduous process for scorpionflies. These insects get their name from the scorpion-like stinger they have on the tips of their abdomens.
But in one genus, Dicerapanorpa, the males have "anal horns". These help them to grasp a female's abdomen during copulation.
A male can lock a female into his embrace for over two hours using his anal horns.
Bats can use sound to sabotage rivals' senses
High up in the sky, Mexican free-tailed bats are waging a war of sound.
These bats can swoop in and steal the prey of competitors by jamming their senses with sound.
Researchers recorded the jamming signals that were emitted and discovered that bats were jammed the very moment they were about to catch a tasty moth. The jamming sound then caused them to miss their prey.
Extraterrestrial bonus entry: On the Moon, humans could walk on water
Humans clearly cannot walk on water on Earth, but we might be able to do so elsewhere.
While some species of insect and lizard can walk on water, humans are far too heavy and slow.
Not so on the Moon, it turns out. The weak lunar gravity means that walking would require less muscle power, and our small feet wouldn't need to move all that fast to avoid sinking.
This research may sound pointless, but these findings could help build "biologically inspired" robots.