The total number of human olfactory receptor cells is about 40 million. The human eyeball is about 24.5 mm long. The octopus does not have a blind spot. The eyes of the chameleon can move independently. Therefore, it can see in two different directions at the same time.
Crabs have hair on claws and other parts of the body to detect water currect and vibration.
Like bats, dolphins use echolocation for movement and locating objects. Each eye of the dragonfly contains 30,000 lenses. The entire body of an earthworm is covered with chemoreceptors. Blowflies taste with 3,000 sensory hairs on their feet. The giant squid eye is 40 cm in diameter.