Monday, January 23, 2017

ALL Otters Week! (whether you like it or not ;)

This week we'll be looking at... wait for it... OTTERS!
Which otters?!?

ALL OTTERS!

We'll take a brief peek each day at what is currently going on with each of the otter species around the world, right now...









First, some basic info about each species. There are 13 known modern species of otters, spread out across 5 of the 7 continents of the world.  Otters are not found in Australia, the surrounding islands, or Antarctica. See map above for distribution of specific species.


 Currently all, but one, of the species are experiencing a decline in populations. Five otter species are considered endangered, 2 are considered vulnerable (or near threatened), 5 are listed as near threatened, and only one of the species listed is in the category of "least concern" by the IUCN Otter Specialist Group.


Otter species status:                                                                  Status                         Population Trend  

Sea Otter ~ Enhydra lutris Endangered Decreasing
North American River Otter ~ Lontra canadensis Least Concern Stable
Neotropical Otter ~ Lontra longicaudis Near Threatened Decreasing
Marine Otter ~ Lontra felina Endangered Decreasing
South American River Otter ~ Lontra provocax Endangered Decreasing
Giant Otter ~ Pteronura brasiliensis Endangered Decreasing
Spotted-Necked Otter ~ Hydrictis maculicollis Near Threatened Decreasing
African/Cape Clawless Otter ~ Aonyx capensis Near Threatened Decreasing
Congo Clawless Otter ~ Aonyx congicus Near Threatened Decreasing
Eurasian Otter ~ Lutra lutra Near Threatened Decreasing
Hairy Nosed Otter ~ Lutra sumatrana Endangered Decreasing
Smooth Coated Otter ~ Lutrogale perspicillata Vulnerable Decreasing
Asian Small-Clawed Otter ~ Aonyx cinereus Vulnerable Decreasing


An introduction to each otter species...

Sea Otter ~ Enhydra lutris

Sea Otters spend their entire lives in the ocean, only leaving the water in the case of extremely bad storms. They are also one of the known tool-using mammals, using rocks to break shells open so they can consume the shellfish inside. It is important that they are able to do this well because they have to eat about 30% of their body weight every day!


North American River Otter ~ Lontra canadensis

North American River Otters are highly adaptable to different types of habitats, but are very sensitive to pollution and changes in water quality. They are extremely playful, and turn almost all regular activities into a game. They do not tend to pair-bond (though sometimes they do), but males will help to raise the pups if given the opportunity. Males tend to be more solitary than females, but they don't do well alone for long periods of time and will seek out the company of other otters.


Neotropical Otter ~ Lontra longicaudis

Unlike most otter species, Neotropical Otters are relatively solitary. Male and female Neotropical Otters meet one day a year for breeding, and then go their separate ways. Neotropical Otters prefer clear, fast-flowing water. Habitat destruction and water pollution are major threats to this species.


Marine Otter ~ Lontra felina

Marine Otters seem to be the only otter other than the sea otter that do not require access to fresh water to wash themselves. Though Marine Otters tend to be solitary, they are generally friendly (but not highly sociable) with other otters. They do sometimes hunt cooperatively, groups of two or three otters working together to catch larger fish. Also, Marine Otters have hairy noses! (Also known as the Sea Cat)

 
Southern River Otter ~ Lontra provocax

Southern River Otters tend to have a very short life span. Few live to maturity, and only 1% live to 10 years of age. They are generally solitary, coming together mainly to mate. The female raises the pups alone, and there are no social groups beyond this.   They have territories like other otters, but the size of these territories is unknown and it appears that they are not particularly defensive of them.

 
Giant Otter ~ Pteronura brasiliensis

From nose to tail, Giant Otters can be up to 6ft long! Their tails are flattened and flanged, and very strong. Their ears are comparably small, and their eyes very large.  Giant Otters are at the top of the Brazilian food chain. They eat fish, small caiman, crustaceans, snakes, and birds. Giant Otters are incredibly sociable, and often hunt in groups. They live in family groups of ten or more, sometimes up to twenty otters!


 
Spotted-Necked Otter ~ Hydrictis maculicollis

Due to genetics work done on otters, this otter has been put in to a new genus, Hydrictis! (more about that in an other post!)
Spotted-necked Otters are fairly small, weighing form 10 to 20 lbs.They live alone or in small family groups, but often form social and hunting groups of five to twenty members. They spend more time in the water than other freshwater species, almost never leaving the water's edge. Resting sites, holts, latrines, and breeding areas are all right next to the water; they are not very agile on land. Like other otters, the Spotted-necked Otter tends to turn everything it does into a game.


Cape/African Clawless Otter ~ Aonyx capensis

The Cape Clawless Otter's feet have almost no webbing, and claws only on the three middle toes of the hind feet. The front feet are very sensitive and hand-like. In fact, they are so dexterous with their front paws that they are left- or right-handed, just like people are. They use their hands to dig for prey in the mud or under rocks. They tend to form loose social and foraging groups with other otters.  Like other otters, they are incredibly playful and are excellent swimmers.They don't spend as much time in the water as other otters, and are willing to travel farther from it in search of a new home. (Also known as African Clawless Otter)



Congo Clawless Otter ~ Aonyx congicus

Congo Clawless Otters' back feet have small claws on the three middle toes, and very little webbing. The front feet have very small claws and no webbing. The front paws are very sensitive, like those of its close relative the Cape Clawless Otter, to increase success in finding food under rocks and in the mud.  Their short fur (providing less insulation) and the abbreviated webbing of its feet make the Congo Clawless Otter the least adapted otter for life in the water. Congo Clawless Otters are mostly solitary, only interacting with other otters when monogamous pairs come together to mate.


Eurasian Otter ~ Lutra lutra

Eurasian Otters are found almost everywhere in Europe and Asia that is near water, fresh or salt, as long as there are freshwater pools nearby for drinking and bathing. They tend to live alone except when mating, when the male and female may stay close together for about a week, or for females, when raising a litter. Though they are excellent swimmers, Eurasian Otters can only hold their breath for about 30 seconds!



Hairy Nosed Otter ~ Lutra sumatrana

Very little is known about the Hairy Nosed Otter. It is endangered and incredibly rare. The nose is completely covered in hair, and the feet are webbed, with strong claws.The major threat to Hairy Nosed Otters is from humans: hunting, habitat competition, destruction, and pollution. Despite efforts to establish a captive breeding program, there have only been three of these otters held in captivity (and unfortunately, all male).





Smooth Coated Otter ~ Lutrogale perspicillata 

The Smooth Coated Otter prefers to live in undisturbed areas. They hunt during the day and at night, sometimes alone and sometimes in large groups. Smooth Coated Otters mate for life, and live in family groups consisting of the mated pair and their pups (often including full-grown pups). The alpha female is dominant and determines hierarchy within the group, while the alpha male moves the group through their territory. Smooth Coated Otters are proficient both on land and in water. They are powerful swimmers, and on land they climb and jump quite well.

 
Asian Small-Clawed Otter ~ Aonyx cinereus

 The Asian Small-Clawed Otter is the smallest of all otter species, and also the most social. They mate for life, and live in family groups of between four and twelve, and sometimes up to twenty, otters. The group hunts, plays, and sleeps together. These otters will travel a long distance out of water in search of new habitats. They don't generally dive deeper than their body length in search of food, and spend more time out of the water than most otter species.
(Also known as Oriental Small-Clawed Otter)




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