Think pollution doesn’t hurt? Ask a polar bear’s penis
Polar bears can’t catch a break. The poster children of climate change and habitat loss, polar bears could be feeling the impacts of human pollution in a very intimate way: in the penis bone and testicles.
Like many other mammals – such as walruses, raccoons, cats, dogs and most primates – polar bears have a bone in their penis called a baculum.
Scientists aren’t quite sure what the baculum is for; it could help support the penis (helping the male mate for a longer time), act to stimulate the female during mating, or it might just be a byproduct of evolution.
But what they have shown is that pollutants – specifically PCBS – could cause osteoporosis in the polar bear baculum, making it smaller and less dense, and cause their testicles to shrink.
Polychlorinated biphenyls (PCBs), were once a widely used as coolant fluids and lubricants in appliances and in the production of goods like paint and cement.
Mounting evidence of PCBs harmful effects to human and environmental health prompted many countries to ban their use during the late 1970s and 80s. In 2001, most nations signed the Stockholm Convention on Persistent Organic Pollutants, agreeing to stop their production and limit their use.
Despite this, PCBs remain persistent in the environment, and are known to accumulate in the bones, tissues and organs of animals that unwittingly eat them.
Christian Sonne at Aarhus University in Denmark led the research team that made the link between these pollutants and polar bear penis bones, and call for more research into the link between pollutants and reproduction in this already threatened bear.
Body hair and bone-breaking in the ‘horror frog’
When it comes to strange body parts, the hairy frog (Trichobatrachus robustus), also called the ‘horror frog’, has a pretty impressive resume.
First up: their hair-like growths. While most frogs are Kermit-smooth, male hairy frogs grow tufty brown patches on their body during the mating season – ladies, get in line. But looking closely, these growths aren’t actually hair: they’re skin.
It’s thought that the hairy frog produces these thin skin strands to increase their body’s surface area, allowing them to take in more oxygen while they look after their new brood of offspring. So these hairy growths could be the signpost of an energetic dad.
Onto their Wolverine feet: the hairy frog is able to break its own bones, pushing them out through the toe pads to create a set of extendable claws.
Researchers from Harvard’s Museum of Comparative Zoology think that this bizarre ability is a defense mechanism. The claw bone is attached to a muscle that, when tensed, breaks it away from the adjacent bones and pulls it downwards to pierce the skin.
The end result looks something like a cat’s claw, and is found in the hind legs of the hairy frog.
Northern quolls: underfed, oversexed
Near the end of the mating season, male northern quolls look pretty worse for wear. With nearly all their muscle mass deteriorated and at a dangerously low body weight, these determined fellas continue to move frantically over their home range looking for females to engage in hours-long mating sessions.
Until they don’t. This exhausting sex-quest will eventually kill them: the northern quoll shags itself to death, and all before its first birthday.
In the animal kingdom, the sex-to-death reproductive strategy is known as semelparity (where an animal dies after its first mating or breeding season). This strategy is common in plants, bacteria and insects, but is rare in mammals.
When looking for love, male quolls search far and wide, increasing their home range to around 10 square kilometres – a lot of turf for a small animal. Female quolls all enter estrus for around three-weeks in late May and early June, and the male’s goal is to mate with as many as he can during this reproductive window.
In the face of death, it’s great to see male northern quolls put their bodies on the line for the continuation of their species. While they used to be common across northern Australia, Northern quolls suffered heavily from invasive species like cane toads, feral cats and foxes and are now endangered.
Luckily, some remote areas like the northern Kimberley and offshore islands are currently cane toad-free, and these places remain home to healthy populations of northern quolls that do it ‘till they die.
Snotty iguanas in the Galapogas
Getting snotty after a dip in the ocean is a pretty common problem. For the marine iguana – the world’s only ocean-going lizard – it’s one they deal with as any self-respecting animal would: a hands-free bushman’s blow.
Marine iguanas hang out in colonies along the shoreline, basking on the rocks like seals, and venture into the ocean to feed on seaweed an algae growing on rocks. But in eating these foods, the iguanas also take in huge quantities of excess salt.
To avoid toxic levels of salt in their bodies, the iguanas expel it through special glands connected to their nostrils. With a little wheeze, they shoot the salt out in a shower of snot, some of which gets on their face, leaving crusty patches.
It might not be pretty, but it’s effective, and has allowed these unique lizards to conquer the seas.