Wednesday, April 23, 2014

Creature Feature #186: Eagle Ray

The Eagle Ray are a group of cartilaginous fishes comprised of a number of species spread across seven Genera. Their horizontally flattened body, with their wing-like fins, is idea for swooping and soaring through the water, and they are even capable of breaching the water and soaring above for several metres before diving back in again. To hide from predators,  he comes to rest on the ocean floor, creating a shallow scrape in the sand and his cryptic, spotted colouration provides camouflage. Eagle Rays are ovoviviparous, with the female retaining the eggs until they hatch and then giving birth to up to four pups at a time.

Tuesday, April 22, 2014

Creature Feature #185: Eagle-Owl

The Eurasian Eagle-Owl is a large, powerful bird with a wingspan of up to 200 centimetres. He is characterised by his ear tufts - which are not ears at all, but merely tufts of feathers. His large size and powerful talons mark him as a formidable predator, and he flies silently through the night, hunting mammals up to the size of a hare. After pouncing, he quickly dispatches the prey with his talors and, if necessary, a sharp peck to the head, before carrying it off to be devoured. Large prey must be consumed on the ground, with the owl risking predation, or losing his supper, to a prowling fox. Small prey is swallowed whole, with the bones and other undigestible bits being regurgitated later as a pellet.

Monday, April 21, 2014

Creature Feature #184: Eagle

The name "Eagle" is given to larger birds of prey. These are characterised by their powerful hooked bills, strong talons and a taste for meat. Most of the species are spread across Eurasia and Africa, but two species - including this Bald Eagle - occur in America. She is an apex predator, an opportunistic hunter with a taste for fish. To hunt for these, she swoops low across the water, scooping the fish up with her talons. Although she is not the largest of eagles, she can carry prey weighting over 6 kilograms for short distances. Pairs are monogamous, courting relatively early in the season with elaborate aerial displays that involve cartwheeling through the air, talons locked together. A very large nest, called an eyrie, is constructed at the top of a tree and this is added to year-by-year. In this she lays one-to-three eggs.

Sunday, April 20, 2014

Creature Feature #183: Devil

The Tasmanian Devil is the largest extant carnivorous marsupial. Once spread across Australia, it is suspected that hunting pressures and competition with foxes and dingo have restricted her range to the island of Tasmania. She is predominently a scavenger, although will prey on wombats and has even been known to kill kangaroo. Roadkill is a more recent favourite, and brings with it inherant risks. Although a solitary hunter, eating is a social occasion and when one Devil discovers a carcass, others will soon gather. With her powerful jaws, the entire carcass will be reduced to nothing with even fur and bone consumed. Unfortunately, the entire species is under threat due to a particularly unpleasant disease - Devil Facial Tumour Disease - a contagious cancer that affects the Devil's face and prevents it from eating leading to eventual death by starvation. Some local populations have suffered a 25-50% decline. Conservation has stepped in to do their best to save the species: removing sick animals, and quarantining healthy ones in captivity.

Saturday, April 19, 2014

Creature Feature #182: Dunnart

There are 21 species of Dunnart, a mouse-sized marsupial found in Australia and New Guinea. Her diet consists predominently of invertebrates and small vertebrates such as frogs. Some species, like this Fat-Tailed Dunnart, can survive in very arid environments. Every night she consumes her weight in food, storing the excess nutrients in her tail in the form of fat. This provides an energy reserve. If conditions get too cold, and food too scarce, she can enter into a state of torpor. Her body temperature lowers, heart rate drops. The Dunnart is unique in being the only mammal capable of doing this while also nursing young. She has also been known to share burrow space, and warmth, with the common mouse - a risky business for the mouse, because she is a predator and has been known to hunt small rodents.

Friday, April 18, 2014

Creature Feature #181: Dung Beetle

The Dung Beetle plays an important role as nature's "clean-up crew". His diet consists partly, or entirely, upon the feces of vertebretes, specifically herbivores, althogh some species supplement their diet with mushrooms, decaying leaves and fruit. He uses his sensitive sense of smell to locate the dung and then rolls it up into a ball - sometimes up to ten times his weight. Sometimes the male and the smaller female will roll the ball together, with her riding on top, or following behind and occassionally assisting. The ball is always rolled straight, regardless of any obstacles. It will be buried in a soft patch of soil and the pair will then mate, the eggs being laid inside this warm brood ball. They then remain to guard their developing larvae.

Thursday, April 17, 2014

Creature Feature #180: Dumbo Octopus

The Dumbo Octopus earns her name from her two ear-like fins, which reminded her discoveries of Disney's flying elephant, Dumbo. She is a deep-sea dweller, living at depths of over 3,000 metres and is thus the deepest diving of any octopus species. She hovers above the ocean floor, searching for invertebrates to scoop up with her barb-covered arms and swallow whole. To move she uses a combination of her fins, her limbs and also by shooting water through her siphon: a funnel that she can use to hold water within her mantle, and then expel it at high speed, thus propelling herself forward.