Hobbies And Interests
Vision
Some seals, the harp seal in particular, have eyes with large spherical lenses along with a dilating pupil, similar to that in humans. The pupil contracts in bright light to produce a focused image. The eyes of harp seals have cone photoreceptors for vision in bright light. It is believed the photoreceptors enable seals to see in some form of color.
Hearing
Harps seals have hearing capabilities in both air and water. The seals' hearing range in air is similar to that of humans. Harp seals do not have external ears but long ear canals partially plugged with wax, making hearing in air less sensitive to that of humans. Seals and humans have similar abilities for determining pitch and background noises as well as the ability to vocalize sounds.
Disease
Both seals and humans are susceptible to influenza viruses. Seals acquire a virus called parapox or seal pox, similar to the chicken pox virus in humans. A seal infected with seal pox is capable of transferring the virus to a human during physical contact. This occasionally occurs when humans rescue stranded seals. Human-to-human transmission of seal pox has not been reported. A human with seal pox exhibits almost identical symptoms to chicken pox and topical treatments to control itch is the only treatment for both types of pox.
Birth
Both being mammals, humans and seals have similar gestation periods and nursing methods. When female seals become pregnant, a three-month delay occurs prior to the growth of the fetus. Once the fetus begins to grow, the female seal is pregnant for nine months. She gives birth to one pup. The pup is nursed on its mother's milk, from two mammary glands, for up to six weeks, depending on the species of seal. The mother seal does not feed while nursing and returns to the sea when she can no longer ignore her hunger. At this time, the pup lives on its own fat stores for up to two weeks then enters the sea to fend for its self.