Sunday, January 23, 2011

Part 2


Galapagos Sea Lion (Zalophus wollebaeki)

They are found in the Galapagos Islands and Isla de la Plata. They are very large, both genders have very thick necks but males are also thick in the chest and shoulder areas. Females are more slender and longer than males are. Males have a crest that is on top of their heads. A characteristic that tells this species apart from others is their long and pointy nose. They feed on a variety of different fish. The males are always more competitive with each other during the mating season. They each breed with five to twenty females. The mating season goes on from May till January, which is much longer, compared to other species of sea lions out there. 

        





New Zealand Sea Lion (Phocarctos hookeri)

The males are about nine feet long and the females are close to seven feet long. They are mainly found around South Island and Auckland Islands. Their breeding season takes place from November until January. 

              





The Australian Sea Lion has a narrow niche. They tend to stay only around the coastal waters of South and West Australia. They can also breed at any time of the year.

3. In the past the Australian Sea Lion was hunted for its fur and oil by the Europeans. In the 18th and 19th centuries it was almost hunted to extinction. The populations are still low today. They are vulnerable to by catch, they can be entangled then eventually drown in gillnets. Smaller Sea lions have been trapped and drowned in pots used to catch rock lobster. 

If the Australian Sea Lion became extinct their food source may grow to very large numbers in their habitat. Their predators, mostly sharks would have to consume on other prey.

The zoo aquarium association and the Taronga conservation society of Australia are both protecting the Australian sea lion existence.





















Friday, December 17, 2010

Structural and Behavioural Adaptations

                                                                                                                                           


Australian Sea Lion - Neophoca Cinerea

     Sea lions have flippers instead of four feet to better suit their life in the water. They also have very streamlined bodies to help them be agile. These adaptations are very helpful with avoiding their predators, sharks, and particularly great whites. They also don't migrate anywhere and tend to stay and feed in near shore shallow waters (20-30 km). They sometimes make use of deeper offshore waters. Their major prey are cephalopods, crustaceans and fish, also occasionally penguins. They hunt them using speed and surprise. They can hold their breath for very long periods of time and can dive up to 100m. A male was measured able to dive 245m. They use their flippers to chase after their prey and catch it in their mouth then swallow it whole. To come on land, they rotate their hind flippers to face forward like a foot they then use their front flipper to propel themselves up on land. This helps them to get on land and be able to reproduce. They breed mainly on offshore islands, rocks and sandy beaches. The males arrive 2-3 weeks before the females because they battle for territories. Their breeding is very unique because they don't have a breeding season. This means that pups can be born at any time of the year.