Saturday, October 29, 2016

Envying Animals, Part 1--Vision, Hearing, Sense of Smell

Every now and then, I think about animal characteristics that I envy. Part 1 of "Envying Animals, …" focuses on three senses—vision, hearing, and sense of smell. Part 2 of "Envying Animals, …" focuses on non-sense characteristics.

Vision
Human vision is amazing for near and far vision, color differentiation, and motion and edge detection. Some animals' vision talents far exceed ours. For example, "10 Examples of How Animals See - Images That Show Us The World Through Their Eyes" describes 10 animals' visions (with images) that contrast with human vision. Two examples of animal vision superiority are birds and butterflies.
Birds have four types of cone cells in their eyes called photoreceptors, while humans only have three. ... Their four types of cone cells let them see red, green, blue, and ultraviolet together. … Butterflies see with red, green, blue, UV, and the wideband light from red to purple.
Other animals that "10 Examples …" features include snakes, cats, and bats.

"Animals That Can See Infrared Light" features boa constrictors and pit vipers, piranha and goldfish, and mosquitoes.

"Snake infrared detection unravelled" describe physical reasons for snakes' infrared vision, an enviable ability.
Vipers, pythons and boas have holes on their faces called pit organs, which contain a membrane that can detect infrared radiation from warm bodies up to one metre away. At night, the pit organs allow snakes to 'see' an image of their predator or prey — as an infrared camera does — giving them a unique extra sense.
"Cat Vision: Cat Vs Human Eyesight" contrasts cat and human vision capabilities.
Cats may have beaten us humans with their field of vision and ability to see in the dark, but we win hands down when it comes to color. While cats are not totally color blind, they do not see the entire array of colors that we do. ...The average cat vision is somewhere between 20/100 and 20/200.
"What If Humans Had Eagle Vision?" describes in great detail about eagles' vision advantages.
Eagles and other birds of prey can see four to five times farther than the average human can, meaning they have 20/5 or 20/4 vision under ideal viewing conditions. … their retinas are more densely coated with light-detecting cells called cones than human retinas, enhancing their power to resolve fine details … they have a much deeper fovea, a cone-rich structure in the backs of the eyes of both humans and eagles that detects light from the center of our visual field.
"Animals with super powers: Sonar hearing, infrared vision, lightning reflexes... A new BBC show reveals the amazing abilities that help animals survive" emphasizes extraordinary vision and other characteristics helpful for certain animals' livelihood.
One advantage of [snakes'] heat sensors is the power to see not just where an animal is but where it has been, leaving traces of warmth like tracks.
Thanks to their [arctic caribou] UV vision, the wolves [grey-and-white pelts] show up as almost black, and their camouflage is useless.
Hearing
Animals that have excellent hearing (much better than humans) include owls, bats, cats, and elephants. "Animals with the best sense of hearing in the world" describes animals that really show that humans have huge disadvantages for hearing acuity.
[Owl] large ear holes are at slightly different heights, above and below eye level, helping them pinpoint the vertical positions of sound sources.
Echolation (echolocation?) [of bats and dolphins] is so accurate that with each chirp, a bat or dolphin can tell the location, size, direction and even the physical nature of an object.
With 30 different muscles, the cat can independently rotate each of its ears 180 degrees, and position one ear or both facing any sound the cat detects.
[An elephant] can hear at frequencies twenty times lower than us. They also use their trunk and feet to hear, both of which are packed with special receptors to pick up on low frequency vibrations.
Like elephants, pigeons can hear sounds at exceptionally low frequencies and this helps to explain their exceptional sense of direction. … Pigeons also possess the equivalent of an in-built compass which allows them to navigate using the Earth’s magnetic field and the position of the Sun.
Besides having excellent hearing, elephants feel vibrations more sensitively than humans do. From "Animals with super powers: …": "Some creatures such as elephants 'hear' distant footsteps by picking up vibrations in their ear bones and through their feet".

Sense of Smell
Three species of animals that are impressive with their sense of smell are dogs, elephants, and sharks.

"Why Do Dogs Have Such a Great Sense of Smell?" contrasts number of smell receptors between dogs and humans and other canine advantages.
A dog contains about 225-300 million smell receptors, as compared to just 5 million of these receptors being present in a human nose. … A dog’s olfactory cortex is about 40 times larger than that of a human. … Dogs contain another special olfactory system above the roof of its mouth called the vomeronasal organ, which helps dogs sense the smells of objects that they cannot see, such as human emotions.
Elephants, on the other hand, also do well in the smell department. "7 Facts You Didn't Know About Elephant Trunks" mentions bloodhounds and elephants—"sense of smell up to four times as sensitive as a bloodhound's … millions of receptor cells housed in the animal's upper nasal cavity". In addition to touting the elephant's sense of smell, the same article describes other features of the elephant's trunk, such as strength for lifting (with over 40,000 muscles), capability of picking up small objects, and snorkeling.

"The 25 Coolest Facts About Sharks" discuss sharks' smell equipment among the article's other shark facts. "Two-thirds of a shark’s brain is dedicated to its sense of smell. … they can detect whether a scent is coming from their right or left nostril to better help them track down their prey."

No comments: