Aquatic mammals that have secondarily taken to water. These are stray reports about sightings of unidentified whales. However occasional cases of whales being cast up on the coasts. Aquatic mammals are a diverse group of mammals that dwell partly or entirely in bodies of water. The level of dependence on aquatic life are vasly different among species with the river dolphins being completely aquatic and fully dependent on aquatic ecosystems. Mammals adaptation to an aquatic lifestyle vary considerably between species. River dolphins and manatees are fully aquatic and therefore are completely tethered to a life in the water. Seals are semi aquatic.
Aquatic mammals can be killed as bycatch from fisheries, where they become entangled in fixed netting and drown or starve. Marine mammals are aquatic mammals that rely on the ocean for their existance. They include animals such as whales and polar bears. Marine mammal adaptation to an aquatic lifestyle vary considerably between species. Increase ocean traffic causes collisions between fast ocean vessels and large marine mammals.
The whales is a marine mammal. It measures up to 30-40 meters and weighs about 200 tonnes. The blue whales body is long and bluish gray with ventral side pale yellow. Dorsal fin is very small. A birth the calf weighs about 3 tonnes and around 5-7 meters. Females are larger reaching sexual maturity at around the age of the five by which they are about 21 m long. Life span of whales is 75 years. Whales lack back limbs and external ears.
Dolphins are marine mammals that are closely related to whales and porpoises. They vary in size from 1-2 meters and 40 kg. They are found worldwide, mostly in the shallower seas of the continental shelves and are carnivores, mostly cating fish and squid.
Manatees are large , fully aquatic marine mammals. Manatees can be found in shallow, slow- moving rivers, saltwater bays, canals and coastal areas. Manatees can grow over 13 feet in length and weight upto half a ton. Life span of manatees is up to 60 years. Manatees eat different type of species of aquatic and semi aquatic.
Sea lions have external ears. There are two types of sea lions.
- Sea Lions
- Fur Seals
The California sea lions native to the south west coast of North America. The Northern fur seal migrates in winter from the bering sea to California and Japan.
They loves water and stay such merged up to 16 hours of the day with its eyes and nostrils set high up to head, it is often tall enough to stay submerged and breathe at the same time. They leave the water at dusk to feed on land vegterian. They weigh 5000 to 8000 pounds. The life span of the hippopotamus is 40 years.