Wednesday, January 2, 2013

Man as hunter

Man as Hunter

  Man is the ultimate apex predator on land and sea. Hunting predates modern man by hundreds of thousands of years. Early human ancestors using simple stone tools were most likely only scavengers that feed on the left over of other predators kills. They were also preyed on by much bigger predators like the big cats, wolves, and maybe even large birds of prey. Over time what the early human ancestors lack in speed, strength, or natural weapons like teeth and claws they made up for in better stone tools and the use of fire.

  As early human ancestors became more intelligent they developed complex language along with complex social interaction and culture. The stone tools and weapons became many different kinds each with a special purpose. They made hunting for large and small game more efficient and safer. Instead of just eating animals early human ancestors starting using every part of the animal for clothes and for their other needs. Later human used hunting in religion, rituals, and storytelling.

  Over 10,000 years ago all human were hunter gathers. That change after the last global ice age. Radical climate change help create farming and pastoral cultures that gradually displace hunter gathers on Earth in all but in a few isolated places. Farming and the domestication of animals created surpluses of food most of the time. That allow for even more complex societies that no longer need hunting as a form of survival. The more complex societies and cultures allowed for more people to share ideas. This led to inventing and discovering new and better way of doing everything. We now live in a culture with technology that is becoming more advance by the day. There have never been more humans on planet Earth. Most people have never lived in better health or longer. Human now have the power to force animals into extinction, change the planets climate, and use up every natural resource if we what. Or we can choose not to.     

Killer Whales

Killer Whales

  Killer whales are the largest of the dolphin and the apex predator of the oceans. They are over 20 feet long and can weigh more than 6 tons. But they are not the biggest predator. Sperm whales are more than 60 feet long and weigh more than 50 tons. Sperm whales dive thousands of feet deep to feed on large and giant squid that live there. 

  The killer whales are found in every part of the world oceans and seas and feed on a wide range of different prey. They are extremely efficient predators. They have teeth are very large and extremely strong. When the large mouth snaps shut the teeth are spaced to fall into their gaps in the top and bottom jaws creating a powerful cutting action. Small animals are swallows whole. Bigger animals can be cut in half. And large whales can have large chunks taken out of them. Killer whales are one of the fastest animals in the ocean. They can keep up their speed over a long period of time running down their prey. 

  Killer whales depend sound for navigation, searching for prey, and communicating with each other. When sound is used for communicating with each other with in a group they use the same sophisticated calls. They are very intelligent they can be trained in captivity. Killer whales in the wild and captivity show individuality, problem solving, inquisitiveness, and playfulness. They teach their calves how to hunt for dangerous prey animals using specific skills and techniques some of which are very complex. 

  The best known killer whales by science live in the Pacific Ocean off the west coast of North America. There are three different independent groups of killer whales that never interact with each other. The best known groups of killer whales called resident killer whales. They reside coastal waters of the northeast Pacific will eat only fish and some squid. The second group is call transients killer whales. They travel along the west coast of North America from Alaska to California preying on marine mammals including grey whales and their calves. The third group is called offshore killer whales. They are the least known. It is believed these killer whales travel far into the North Pacific Ocean feeding on large schools of fish, marine mammals, and sharks. Killer whales in the wild as have never been known to kill a human. 

  Killer whales live in complex stable social structure base on matrilineal family groups. They use sophisticated hunting methods and behaviors and then pass them on to the next generation. Some biologists believe this is a culture whales live within. Different groups of killer whales live in different parts of the ocean feeding on different prey using different methods. They all live in different cultures using different vocal behaviors unique to that group.

Polar Bears

Polar Bears

 Polar Bears is the world's largest predator on four legs and the most carnivorous of all bears. Adult Polar bear males can weigh as much as 1,500 pounds. They are the most powerful predator on land. Their range includes all major landmass in the Arctic Circle. Polar bears live in Greenland, the Svalbard archipelago, Russia, Alaska and Canada. It is one of the largest bears along with the Kodiak brown bears. Kodiak bears on the Kodiak archipelago in Alaska and are the largest of the brown bears. They are about as large and heavy as polar bears but it is an omnivore that will eat carrion, salmon, and berries. Only a few of these brown bears will prey on deer and mountain goats.

  The polar bears are called by many biologists a marine mammal because they evolved many adaptations from the brown bears for the extreme cold of the Arctic Circle. They have a thick layer of blubber and two layers of fur that cover their black skin. The under coat is very dense thick fur. The outer layer of fur is the transparent guard hairs that appear white or light tan. The polar bears lose very little body heat. They are so adapted freezing winters polar bears easy over heat in arctic summers. Polar bears paws are modified for ice and water of the arctic. They are superb swimmers that will cross open water between ice floes. Its blubber allows it to float as they dog paddles using their front paws. Like most bears they can run very fast in short burst.  

  They use their exceptional sense of smell to find carrion and prey. With a seal resting on the ice floes the polar bear will sneak up on the prey within 40 feet before using a final burst of speed to catch the seal before it escape. Polar bears will search for seals pups in the seals breeding season. The favorite hunting method is to find the seals breathing holes. The seals need to return to breathing holes when they swim under the ice. Polar bears after they find one of them quietly waits close by for the seal to break the surface to take a breath. The polar bear will attack pulling the seal onto the ice then killed it by crushing it skull with its powerful jaws. Adult bears will first eat the energy rich fat. Younger smaller polar bears will scavenge the leftovers from other bears kills until they become successful predators themselves. Polar bears are powerful enough to kill adult walrus and beluga whales. Both are larger and heavier the polar bear and it is not unusual they are able to escape the bears attack. The adult walrus has very thick skin and two long ivory tusks they use for defense. A healthy adult walrus can put up more of a fight than polar bears can deal with so the walrus calves are targeted instead.   



  Barracudas are opportunistic saltwater predators and scavengers found in tropical and subtropical oceans worldwide. Unlike sharks they are bony, ray-finned fish that have large swim bladders fills with gas. It is used to create neutral buoyancy for the fish in the water column so that it is not sinking or floating at a chosen depth. Barracudas hunt by sight using large eyes. Adults are mostly solitary predators but it is not uncommon to find schools of smaller younger barracudas. They can grow six feet long with a large pointed head and large powerful jaws with many different large sharp teeth. Barracudas have a long stream line torpedo like body coved with smooth scales and many dark spots or stripes on their sides. They use surprise and speed to ambush their prey. Barracuda prey any other fish that is weak or injured killing them by tearing off chunks of their flesh using large sharp fang like teeth. Barracudas attacks on people are rare in spite of their fearsome looks and size. People are far more dangerous to them. They are a favorite game fish and a popular to eat.     



  Sharks, ray, and skates, are fish that have a skeleton made of cartilage instead of bone. Cartilage is made of dense elastic connective tissues. It is the main component is collagen proteins forming the fibrous tissues. It is less rigid or as hard as bone but much lighter. All sharks have from 5 to 7 gill slits on the sides of the head depending on the species. Unlike bony fish they do not have gas filled swim bladder. Most sharks use a very large liver filled with oil instead.
  Earliest known primitive sharks found in the fossil record go back more than 400 million years. Sharks can be found in all but the most extreme parts of the world’s ocean. Bull sharks, sawfish, and the river sharks can survive in both seawater and freshwater. They can be found in fresh water rivers. Sharks bodies are completely covered the tooth like dermal denticles that reduces drag as the shark swims. They have several rows of teeth ready to replace those already in use. Teeth are regularly replaced throughout lifetime of the shark. Their jaws are not attached to their heads like the bony fish. Sharks have keen sense of smell and can detect as little as one part per million of blood in seawater. By swimming at different angles the can get the direction of where the blood is coming from. Sharks have organs called ampullae of Lorenzini that can detect electromagnetic fields produce by living animals and possibly used for navigation. Hammerhead sharks can find stingrays hidden in the sand by sensing the electromagnetic fields produce by the fish itself.  

  The great white shark is the largest predatory shark in the ocean. Whale Sharks are the world’s largest fish much bigger than the great white. Basking sharks and the Manta Rays can grow larger and heavier. They are filter feeders eating tiny plankton, zoo-plankton, and small fish floating in the ocean. None of these larger fishes are predators. Some individual great white’s caught by fishermen are over 20 feet long and weigh over 2 and half tons but most great whites average 15 feet and one ton.

  Great white live in sea and travel deep under water for thousands of miles to feeding or breeding grounds. But the greatest numbers of large adult great whites are found in the coastal waters of the United States, South Africa, Japan, Mediterranean, South America, and around many islands in the Pacific Ocean. Any where there are large concentrations of marine mammals they feed on.

  The great white shark is not an apex predator in the ocean. They are killed by bigger, smarter, faster killer whales. White sharks prey on large fish, whales and dolphins, seals, fur seals, and sea lions, along with other smaller prey. After reaching adulthood the food source becomes marine mammals because they have a large amount of fat and blubber in their bodies. The hunting method depends on the prey. For the most part it is a high speed ambush attack from below. With larger prey like the elephant seals they will wait for it to bleed to death before it starts feeding.