Where did Otariids originate?
The Otariidae, or “eared seals,” evolved around the rim of the North Pacific Ocean 11–12 million years ago and subsequently spread into the Southern Hemisphere. Otariids comprise 16 species. All breeding sites they use are between 60°S and 55°N latitude.
What’s the definition of a pinniped?
Definition of pinniped : any of an order or suborder (Pinnipedia) of aquatic carnivorous mammals (such as a seal or walrus) with all four limbs modified into flippers.
Is a walrus a pinniped?
Walrus are the largest pinniped. Seals, sea lions, and walruses belong to a group of marine mammals called pinnipeds, referring to their flippered feet. Seals (true seals or earless seals) have no external ear flaps.
Where can pinnipeds be found?
Members of this suborder are found around the entire globe, including the Arctic and Antarctic regions. One genus, Pusa (which includes the Ladoga ringed seal, the Saimaa ringed seal, and the Baikal seal) has established a niche in fresh water habitats, whereas the remainder is marine.
When did phocids and Otariids diverge?
approximately 19 Ma
Both otariids and odobenids are known from the North Pacific, diverging approximately 19 Ma, with phocids originating in the North Atlantic or Paratethys region 19–14 Ma.
What did pinnipeds evolved from?
Pinnipeds evolved from the ancestors of the musteloids which include everything from the red panda to skunks, badgers weasels, and raccoons. One potential ancestor was Puijila, an otter-like creature with a long tail and webbed feet that likely lived by freshwater lakes about 24 million years ago.
Why are seals called pinnipeds?
The word “pinniped” means fin- or flipper-footed and refers to the marine mammals that have front and rear flippers. This group includes seals, sea lions and walruses — animals that live in the ocean but are able to come on land for long periods of time. Millions of years ago, the ancestors of pinnipeds lived on land.
Is a dugong a pinniped?
Marine mammals are classified into four different taxonomic groups: cetaceans (whales, dolphins, and porpoises), pinnipeds (seals, sea lions, and walruses), sirenians (manatees and dugongs), and marine fissipeds (polar bears and sea otters).
Is a penguin a pinniped?
Diet is strictly carnivorous, but pinnipeds eat a variety of prey ranging in size from krill, which is filtered from the water by the complex cheek teeth, to, in the case of the leopard seal (Hydrurga leptonyx), penguins and even other pinnipeds.
How do pinnipeds reproduce?
Most males mate with multiple females, but some pinnipeds are monogamous. Mating and birth occur on coastal land or ice or on ice floes. Implantation of the fertilized eggs is delayed, with the result that gestation can last from 8 to 15 months.
Which is a characteristic of Phocids?
Phocids are characterized by the absence of external ear pinnae, a short muzzle, beaded vibrissae, dark skin, short fur, generally two teats in females, internal testes, furred hindflippers, pachyostotic (dense) ear bones, inflated tympanoperiotic bones, and the absence of supraorbital processes or an enlarged sagittal …
Are phocids polygynous?
All species seems to be polygynous. The three forms of polygyny – female defence, resource defence and lek systems – can be observed in both Phocids and Otariids. Many Otariids exhibit lek-type mating systems intermediate between classical leks and resource defence.
Where did phocids evolve from?
Other early fossil phocids date from the mid-Miocene, 15 million years ago in the north Atlantic. Until recently, many researchers believed that phocids evolved separately from otariids and odobenids; and that they evolved from otter-like animals, such as Potamotherium, which inhabited European freshwater lakes.
When did phocids and otariids diverge?
What are the characteristics of pinnipeds?
Pinnipeds have four webbed flippers used to propel their spindle-shaped bodies. Their sensory organs are adapted to function in both air and water: large eyes and well-developed whiskers allow feeding in dimly lit water; tail and external ears are small, limiting drag.
Do SEALs have balls?
Seals, however, perhaps reflecting their ever-so-slightly-better-adapted-to-water features than sea lions, do not have a scrotum at all. Instead, their testes are stored just beneath the skin, outside of the main body cavity, and not insulated by much in the way of blubber.
How many nipples does a seal have?
Have external ear flaps. Have four teats.
What is a Dugo?
Dugongs are cousins of manatees and share a similar plump appearance, but have a dolphin fluke-like tail. And unlike manatees, which use freshwater areas, the dugong is strictly a marine mammal.