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Porpoises produce ultrasonic clicks, which are used for both navigation (echolocation) and social communication. In contrast to many dolphin species, porpoises do not form large social groups. Porpoises were, and still are, hunted by some countries by means of drive hunting.
The back of its body is dark grey, sometimes almost black, and its abdomen is light. Females reach adulthood in 4 years and reproduce in late spring or early summer. Pregnancy lasts 9–11 months. Females birth one cub, which is born with its tail in front and must immediately rise to the surface for its first breath.
Harbour porpoises tend to be solitary foragers, but they do sometimes hunt in packs and herd fish together. [10] Young porpoises need to consume about 7% to 8% of their body weight each day to survive, which is approximately 15 pounds or 7 kilograms of fish. Significant predators of harbour porpoises include white sharks and killer whales (orcas
Cetaceans have lungs, meaning they breathe air. An individual can last without a breath from a few minutes to over two hours depending on the species. Cetacea are deliberate breathers who must be awake to inhale and exhale. When stale air, warmed from the lungs, is exhaled, it condenses as it meets colder external air.
Humpback whale breach sequence. A breach or a lunge is a leap out of the water, also known as cresting. The distinction between the two is fairly arbitrary: cetacean researcher Hal Whitehead defines a breach as any leap in which at least 40% of the animal's body clears the water, and a lunge as a leap with less than 40% clearance. [2]
A humpback whale (Megaptera novaeangliae) A leopard seal (Hydrurga leptonyx). Marine mammals are mammals that rely on marine (saltwater) ecosystems for their existence. They include animals such as cetaceans (whales, dolphins and porpoises), pinnipeds (seals, sea lions and walruses), sirenians (manatees and dugongs), sea otters and polar bears.
The single blowhole of a bottlenose dolphin just before going under again The V-shaped double blowhole of a gray whale. In cetology, the study of whales and other cetaceans, a blowhole is the hole (or spiracle) at the top of the head through which the animal breathes air.
Porpoises range in size from the vaquita, at 1.4 metres (4 feet 7 inches) in length and 54 kilograms (119 pounds) in weight, to the Dall's porpoise, at 2.3 m (7 ft 7 in) and 220 kg (490 lb). Several species exhibit sexual dimorphism in that the females are larger than males.