Cat Whiskers and Narwhal Tusks: Why Things Are
In the animal world, unique features often have well-designed functions.
Why cats whisk: Cat whiskers are not just for looks, like a man’s beard and moustache. In cats, mice and other mammals, they connect to sensitive neurons in the whisker follicles, reports Live Science. Since cats often search in the dark, the whiskers provide expanded tactile sensitivity to their environment. “A cat’s whiskers — or vibrissae — are a well-honed sensory tool that helps a cat see in the dark and steer clear of hungry predators,” Elizabeth Palermo writes. Look at your cat carefully and you will also find them on the animal’s ears, eyebrows and forelegs. “By brushing its whiskers against an object, a cat can detect the precise location, size and texture of the object, even in the dark,” she continues. “This feature proves particularly useful for a cat trying to gauge whether it can fit into a tight space. Whiskers also detect changes in air currents, helping cats detect approaching dangers.”
Why narwhals tusk: A tooth that can grow nine feet long, the tusk of the narwhal (a type of Arctic whale) might be a sensor, National Geographic and the BBC News report. The tusk, longest on males, makes the animal look like a marine unicorn. Theories vary about its purpose. Most have thought it plays a role in sexual display and attracting mates, since females only grow small ones; others have proposed they use it as an ice pick or acoustic probe. A new theory considered that sensitive blood vessels reach all the way to the end, suggesting it is a sensor that perhaps records water temperature or salinity. Since narwhals are difficult to study, “we may never know for sure how the whale uses its tusk.”
Sea camel drink: Sea snakes, despite being surrounded by water, get thirsty in the ocean for fresh water. Tia Ghose at Live Science, calling the creatures “camels of the ocean,” reports on a new study that shows sea snakes can go for six to seven months before drinking. They will either return to land for fresh water, or find it at the surface when rain falls. Unlike marine organisms like whales and seals, they do not have salt glands to process seawater; yet they can spend months far out in the ocean hunting for fish. It must have been tricky for the University of Florida team to study them while avoiding their venomous bite.
Fruit fly stabilizer: The tiny fruit fly would seem to be at the mercy of the wind, but a paper in PNAS says that they have stabilizers. When flying, they “stabilize their vision-based velocity controller by sensing wind with their antennae.” Vision alone is too subject to delays, the researchers found, to account for their aerial agility; it would send them into a tumble. “Mechanoreceptors on the antennae of flies cannot measure groundspeed directly, but can detect changes in airspeed more quickly,” they found. “By integrating information from both senses, flies achieve stable regulation of flight speed that is robust to perturbations such as gusts of wind.”
Sandhill crane migration: Seen briefly in Flight: The Genius of Birds, sandhill cranes are large, thin birds that cover a lot of territory. A photo gallery on Live Science shows them in various locations and tells about their “amazing migrations.” With their long legs, long necks and long beaks, sandhill cranes mate for life, dance, and are found across the world. They fly from Mexico to Canada, and from Florida to California, covering 400 miles a day. “There is some evidence that the Sandhill Crane is the oldest known bird species on Earth” (of those alive today), Linda and Dick Buscher comment. “A crane fossil found along the Platte River in Nebraska is estimated to be some 10 million years old and identical in structure to the modern Sandhill Crane.”
If a sandhill crane has not evolved in 10 million years, then evolution has been falsified again, along with the mythical 10 million years.
Each animal on this planet is worth getting to know. The more we learn, the more design is obvious. It’s only in sweeping generalizations that evolution gets its pseudo-credibility.