Crocodiles Eat Stones
The stomach of a crocodile is a rocky place to be, for more than one reason. To begin with, a croc’s digestive system encounters everything from turtles, fish and birds to giraffes, buffaloes, lions and even (when defending territory) other crocodiles. In addition to that bellyful-o’-ecosystem, rocks show up too. The reptiles swallow large stones that stay permanently in their bellies. It’s been suggested these are used for ballast in diving.
Whale Milk is 50% Fat
Nursing a newborn is no “small” feat for the whale, whose calf emerges, after 10 to 12 months in the womb, about a third the mother’s length (that’s a 30-foot baby for the Blue whale). The mother squirts milk into the newborn’s mouth using muscles around the mammary gland while the baby holds tight to a nipple (yes, whales have them). At nearly 50 percent fat, whale milk has around 10 times the fat content of human milk, which helps calves achieve some serious growth spurtseas much as 200 pounds per day.
Birds Recognize Landmarks
Can you imagine a road trip vacation without missed exits, stubborn drivers or map-folding disasters? Of course noteyou’re not a bird. Pigeons can fly thousands of miles to find the same roosting spot with no navigational difficulties. Some species of birds, like the Arctic tern, make a 25,000 mile round-trip journey every year. Many species use built-in ferromagnets to detect their orientation with respect to the Earth’s magnetic field. A November 2006 study published in Animal Behaviour suggests that pigeons also use familiar landmarks on the ground below to help find their way home
Many Fish Swap Sex Organs
With so many land creatures to wonder at, it’s easy to forget that some of the weirdest activities take place deep in the ocean. The strange practice of hermaphroditism is more common among species of fish than within any other group of vertebrates. Some fish change sex in response to hormonal cycle or environmental changes. Others simultaneously possess both male and female sex organs.
Giraffes have Unique Blood Flow
The stately giraffe, whose head sits some 16 feet up atop an unlikely pedestal, adapted his long neck to compete for foliage with other grazers. While the advantage of reach is obvious, some difficulties arise at such a height. The heart must pump twice as hard as a cow’s to get blood up to the brain, and a complex blood vessel system is needed to ensure that blood doesn’t rush to the head when bent over. Six feet below the heart, the skin of the legs must then be extremely tight to prevent blood from pooling at the hooves.
Elephants are Smart
Elephants have the largest brain, nearly 11 pounds on average of any mammal that ever walked the earth. Do they use that gray matter to the fullest? Intelligence is hard to quantify in humans or animals, but the encephalization quotient (EQ), a ratio of an animal’s observed brain size to the expected brain size given the animal’s mass, correlates well with an ability to navigate novel challenges and obstacles. The average elephant EQ is 1.88. (Humans range from 7.33 to 7.69, chimpanzees average 2.45, pigs 0.27.) Intelligence and memory are thought to go hand in hand, suggesting that elephant memories, while not infallible, are quite good.
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