Orcinus Orcas are Different from Other Organisms
...im at speeds of 2-6 miles per hour. “Whales swim by moving their tail (flukes) up and down. Fish swim by moving their tails left and right” (Zoom Whales, 2002). Bone is not present in the flukes of killer whales; they are made of muscle and dense fibrous tissue. Arteries supply the flukes with blood and are surrounded by veins to stabilize the orca’s temperature (Animal Information Database, 2001). An orca’s main mode of transportation is swimming but they also do quite a bit of diving. Orcas will start out with three to five short dives followed by a series of longer dives. Orcas don’t usually dive deep but are capable of reaching depths of 100-200 feet. Orcas surface to the water every four to five minutes while they are diving taking two to five breaths before another dive (Animal Information Database, 2001). Orcas have adaptations that have helped them conserve oxygen under water while diving. “When diving, blood is shunted away from tissues tolerant of low oxygen levels (like the extremities) and channeled toward the heart, lungs, and brain where more oxygen is needed.” A higher concentration of myoglobin is present in the muscles of orcas to prevent oxygen muscle deficiency and helps to conserve oxygen during a dive. While an orca dives, its lungs collapse. It forces air into the windpipe and nasal ducts, where internal body surfaces cannot absorb nitrogen and cause decompression sickness (Animal Information Database, 2001). Digestion An orca eats about 3% of its body weight each day. This averages out to be around 551 pounds of food a day (Animal Information Database, 2001). Its diet is made up of fish, squids, seals, sea lions, walruses, birds, sea turtles, otters, other marine animals, and penguins. Orcas have also attacked the blue whale which is the largest whale (Simon and Schuster, 1968, p.86). Orcas are able to succeed at this because they hunt in pods. Orcas are at the top of the food chain and their only enemy is humans (Orr, 1966, p. 172-174). Orcas are homodont and have interlocking teeth. This helps them for tearing and ripping prey but they are not used for chewing (Kellogg, 1928, p. 177). An orca’s throat is large enough to swallow small seals and walruses whole. Orcas have about 40-56 teeth in all, 10 to 14 on each side of the jaw (Wursig, 1989, p. 1550). Orcas tongues are not specialized. Taste buds are not present and it is believed that they have a slight sense of taste. After the food enters the mouth and is swallowed, it travels through the esophagus where no glands are present to break down food. The food will then enter the stomach. Orcas have complicated stomachs. They are composed of chambers where each compartment will secrete different enzymes to break down nutrients. After food passes the stomach, it will reach the duodenum or anterior part of the small intestine (Orr, 1966, p. 172-174). Carnivores have a harder time digesting food so a very long and thin intestine is present to slow down digestion. After the food is digested in the small intestine, it goes through the caecum, large intestine, and out the anu Respiration and Circulation Unlike fish who breath through gills, orcas breath through lungs and have a four chambered heart (Orr, 1966, p. 171). They have one blowhole at the top of their head that acts as a nostril. Muscular flaps cover the blowhole to keep water from entering while under water. The orca’s blowhole leads to its trachea and then to the lungs. An orca does not breath through its mouth. They are only able to breath through their blowholes at the waters surface and hold their breath while under water (Zoom Whales, 2002). The trachea and esophagus of orcas are not connected (Orr, 1966, p. 171). According to the Animal Information Database, “Heat loss in water is about 27 times faster than in air at the same temperature” (2001). On the other hand, orcas are able to maintain a high body temperature by having a thick layer of blubber under the skin, a small surface area exposed to the environment, a higher metabolic rate than land animals to generate body heat, and they breath less often to decrease the loss of body heat (Walter-Sayles, 1949, p. 78). Nervous System “The paralimbic lobe is a unique feature of the Cetacean cerebral cortex not found in other mammals. It is a specialized region in which all specific sensory (hearing, touch, vision, taste) and motor areas are represented together” (Orr, 1966, p. 176). This paralimbic lobe makes perception and information to orcas far more advanced than humans. Senses in orcas are far different than a human’s senses. They are able to sense magnetism. Orcas use the magnetic field of the Earth for navigation but it is still uncertain how they use it. Smell is nonexistent in orcas and their sense of taste is very limited because of the lack of taste buds. An orca’s eyesight is present but it is only used in shallow water or at the surface (Enchanted Learning Software, 2002). Although orcas possess little or no smell and taste, they are very sensitive to touch, and hearing. Because of their excellent hearing, orcas use echolocation (also known as sonar) to sense objects. According to the Animal Information Database, “They make short, intense, broad-band pulses of ultra-sonic sound which bounce off objects near it. The animal “hears” the objects in its environment, cr...