For example, in the seas around Indonesia and Australia, which are among the richest in the world, marine mammals are virtually absent, as are penguins and other swimming birds.
This riddle has a simple answer, Grady argues in a new study —but one with chilling implications for the future of seals, penguins, and whales. Grady and his team considered the possibility—warm-blooded animals need a lot to fuel their gas-guzzling metabolism. Perhaps colder waters are just richer in algae, plankton, and small fish? Read: Why whales got so big. The real explanation for that pattern, the team says, is deceptively simple.
Since birds and mammals can keep heating their bodies in frigid conditions, they remain fast and alert. By contrast, the fish they hunt become slower and dumber. At some tipping point of temperature, seals, dolphins, and penguins start outswimming their prey. They become more likely to encounter targets, more likely to catch them, and more likely to outpace cold-blooded predators of their own.
By monopolizing food in the poles, these creatures can then specialize on specific types of prey, which makes them more likely to split into separate species. Consider the mammals and birds that, bucking the trend, do thrive in the warm tropics.
Accompanied by an ornithologist specializing in penguins, students walked through Stony Point observing the penguins in their natural habitat. They witnessed penguins nesting, molting, mating, and diving in the water during their hour-long visit. I feel like I learned so much in these few hours about the various species that are endemic to South Africa. After Stony Point, the group proceeded to the South African Shark Conservancy SASC where students heard presentations from marine biologists about the health of the oceans around South Africa and how species like the Great White Shark are adapting to shifts in the marine environment.
The major threats facing Great White Sharks, but also the larger shark population, are fishing, bycatch unwanted fish caught during commercial fishing , shark finning, habitat destruction, and climate change.
I realized just how threatened the oceans are and how intense the issues with plastics are. There is very little funding in the Western Cape for shark conservation, which makes studying these animals difficult, but the South Africa Shark Conservancy is committed to researching sharks as a means of conserving them. Their work includes shark tagging and tracking, species surveys, and behavioral observation, which students got to see firsthand at their marine lab.
The SASC currently has three rarely studied species of shark in their tanks that they are observing and monitoring before releasing them back into the wild.
After learning about these specific species of shark, students had the opportunity to hold and them. Many species of terns and petrels spend at least part of the year near the Antarctic continent. In fact the south polar skua a hawk like scavenging bird of prey has been seen as far as the south pole! In addition, cormorants, or shags, are also found all over the Antarctic. There were nesting colonies image 13 of imperial cormorants near Palmer station as well as numerous nesting pairs of giant petrels image 14 and skuas.
But the most beautiful flighted bird I saw was the giant wandering albatross image The wandering albatross is the largest flying bird in the world, with a wingspan of up to ten feet. It nests at the top of cliffs. They are so large that they cannot take off in the normal fashion. They need either a strong wind or they need to take off from atop a cliff in order to gain enough speed to generate enough lift to keep its large body in the air.
Once in the air, they are very graceful, gliding along with barely a wing beat. The seals are also conspicuous members of the Antarctic wildlife community. There are a number of different species, all of which spend some or all of the year in Antarctic waters. The most common seal is the crabeater seal.
In fact, the crabeater is the most common large mammal in the world. It's title is a misnomer, as there are no known species of crab in the Antarctic. The main prey item of the crabeater is krill. Krill comprise a large portion of the diet of all the animals that I have discussed thus far. All Antarctic penguins, whales, and seals rely heavily, sometimes exclusively on krill as a food source.
Crabeaters rarely come ashore, and will occasionally haul out onto seaice. They are hunted by killer whales and leopard seals, and many animals bear the scars of previous encounters with these predators.
The weddell seal image 16 is named for the early British explorers who first encountered these large but docile creatures. The weddell seal is a curious animal, and will frequently use dive holes cut by humans as a breathing hole. They, too spend much of their time at sea, feeding on squid and krill.
I saw many southern elephant seals image 17 during my trip. These large animals would frequently haul out to pup or bask in the springtime sun. The males were simply enormous, weighing up to five tons! They would compete with each other image 18 for the mating rights to harems of females. While these seals only showed a mild disdain for man, I would certainly think twice before passing too closely to a beachmaster.
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