Have you seen these amazing cetacean photos by photographer Bryant Austin?
Posts tagged wildlife.
Southern right whale dolphin (Lissodelphis peronii)
Spectacled Porpoise (Phocoena dioptrica)
The spectacled porpoise gets its name from the dark circle surrounding its eyes. Little is known about this porpoise, and most knowledge has been collected from stranded animals. Despite the fact that the species is not often sighted at sea, biologists believe it to be more abundant than what is suggested. The markings of the robust body are very distinct, the top half is black and the bottom half is white. The dorsal fin is quite large and rounded and the length ranges from 1.3m-2.2m. Most sigthings are from the southern Atlantic coast of South America but confusingely enough, some records are from offshore islands which suggests that the species is curcumpolar in sub-Antarctic and low Antarctic waters. It has been seen off the cost of Brazil, the Falkland Islands, South Georgia, Auckland, Tasmania, south Australia, Heard Island and Kerguelen. The animal has rarely been observed in the open sea.
Every year around 2000 whales, dolphins and porpoises beach themselves, and little is known about why. Some species seem to be more inclined to strand in large numbers than others, and these are all toothed whales; sperm whales, pilot whales, killer whales, beaked whales and some oceanic dolphins. These species normally live in large, tightly knit groups and mostly in deep waters. Solitary species and those living in shallow waters are rarely victims of mass strandings.
When a single animal strands itself, it mostly has to do with it being injured or sick. Mass strandings, on the other hand, remains an unsolved mystery. It is believed that the strong social bonds between the whales might be a factor here, in the way that if one animal is in danger of stranding, the rest of the pod will follow it and subsequently beach themselves as well.
Cetaceans have a complicated echolocation system and some scientists believe that the system may have difficulties detecting gently-sloping coastlines, so to the whales it might look as though they’re heading for open water.
If a beached animal doesn’t get back into open water again it might die from dehydration, drowning (if the tide covers the blowhole) or, for larger whales, by crushing its own organs due to its enormous weight.
If you ever come across a stranded cetacean, this is what you should do:
- Get expert help via the local police as quickly as possible, and while waiting for them:
- Keep the animal’s skin moist.
- Erect a shelter to provide shade.
- Keep the flippers and flukes cool.
- Keep onlookers at a distance.
- Make as little noise as possible.
- Try to keep the animal upper side up.
South Asian River Dolphin (Platanista)
Since the 1970’s and until 1998 the South Asian River Dolphin was considered to be two separate species, the Indus River Dolphin (Platanista gangetica minor), and the Ganges River Dolphin (Platanista gangetica gangetica). This was due to differences in skull structure, vertebrae and lipid composition.
However, in 1998 the classification changed and they are now considered the only two subspecies of the genus Platanista. Externally, the two subspecies look identical, but they are geographically separated around the great rivers that have given them their names.
Among all cetaceans, the South Asian River Dolphin is the only one lacking a crystalline eye lens, thus making it blind. Instead, the species find food using echolocation.
Uniquely among cetaceans, the South Asian River Dolphin swim on one side, usually by leaning to the right and cruising near the bottom of the river.
Northern Bottlenose whale (Hyperoodon ampullatus)
The northern bottlenose whale’s appearance is quite distinct due to its bulbous forehead. This whale is very inquisitive and frequently approaches boats; this, in combination with the fact that they tend to stay with wounded companions, made them easy targets for whalers, who in 1850-1973 killed tens of thousands of individuals. The northern bottlenose whale is found in deep waters of the north Atlantic ocean where dives of up to two hours have been observed.
Common dolphin (Delphinus delphis)
There are two recognized species of the common dolphin, the short-beaked and the long-beaked. The appearance varies so much that more than 20 different species have been suggested. Common dolphins are easily recognized by a distinct hourglass pattern on each side of the body, and the species is sometimes referred to as the hourglass dolphin. The common dolphin is often found in large schools of hundreds and even thousands of individuals. It is a very active dolphin, and frequently porpoises, bow-rides, flipper-slaps, somersaults, lobtails and breaches.