Animal

If you want to know more about humans and great apes, you should grab the book The Third Chimpanzee by the American scientist author Jared Diamond.

Why do men have the longest penises? Chimps the largest testes? And orangutans (or gorillas) the shortest phallus and smallest testes?

What prevents us from having six sequential sets of teeth like an elephant, rather than just baby teeth and adult teeth? After all, with four more natural sets, we wouldn't need fillings, crowns, and dentures as we get older.

After getting my curiosity on animals hooked, I went on to borrow another book by a British-American science writer Ed Yong: An Immense World. The Pulitzer-winning writer covered insects, primates, bats, birds and dolphins. He told stories about the great sensory gifts of different animals. 

Animal senses are simply amazing. Ed Yong has a wonderful word for this sensory bubble - Umwelt. That's a word borrowed from German, and first used by a German zoologist in 1909 to mean an animal's sensory environment. Every creature has its own Umwelt. Every species has its Umwelt that another cannot sense. The Umwelt, as a matter of fact, can be even peculiar to an animal's embryos. 

On an evening of 1991, after suffering from the clouds of mosquitoes at Costa Rica's Corcovado National Park, a scientist checked on the red-eyed tree frogs' embryos every 15 minutes. Those eggs were encased in jelly and stuck to leaves overhanging the pond water. In the dark, nocturnal cat-eyed snake came to grab an omelette dinner made of the tasty tree frog eggs. But it's not that simple. The frog embyros' sensory bubble, or Umwelt, extends beyond the actual jelly bubble. The embryos are highly capable of detecting the vibration from the attacking snake's bite. The shaking triggers the sensitive hair cells, which send signals to their brains, setting off a cascade of enzyme release and disintegration of the eggs. Within seconds, tadpoles are tumbling down too quickly to count, and the snake, still chewing its first mouthful, is left with a smear of empty jelly.