The competition to father young is often most intense behind the scenes.
Snakes have survived millions of years by using their bodies in increasingly creative ways.
Meet the brawny bug with a concoction so caustic it'll make a toad vomit.
How do different species have sex? Medieval illuminated manuscripts contain some surprisingly varied depictions.
Pond snails use things like rocks or the side of their aquarium as their bed, attaching themselves while they sleep. This might not seem very relaxing but their shells do hang away from their body.
Capuchin monkeys understand fairness, sheep recognise their friends, rats make sacrifices for buddies. Yes, animals are sentient. Here's the science.
Male Birds of Paradise have patches of super-black plumage that absorb 99.95 percent of light. New research identified their feathers' microscopic structures that make them look so very dark.
Worldwide, hedgehogs are disappearing at the same rate as tigers.
Chocolate poisoning in dogs remains a problem, particularly at Christmas.
Museums are not apolitical, and they are not entirely scientific. As such, they don’t really represent reality.
Either medals or destruction appears to await canine companions from the battlefield.
This multi-billion pound industry increasingly involves organised crime groups, who see wildlife as a low risk route to profit.
The very existence of kindness and altruism seems to contradict Darwin’s theory of evolution. So how could kind behaviour have evolved?
When lawyers represent the interests of abused animals in the courtroom, they help human victims too.
The short answer is no. But worms can use different parts of their body to do some of the jobs that our tongues do - like tasting and crushing food.
The animals can see you as a threat, so make them feel at home.
Keeping pets is a habit that goes way back into our hunter-gatherer past, and has played an important part in our evolution.
Dogs, rats, cats, cows, chickens and mice have also changed the world.
When humans are happy, they may smile, or laugh, or dance - but what do animals do? Melissa, age 12, wants to know how she can tell if her cat is happy and likes you.
The animal kingdom is full of lefties and righties, although rarely is the ratio skewed as much as it is in humans. If you're wondering about your own pet, you can find out with a simple experiment.