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)

Otter Species ~> Sea Otter

Sea Otter

Size: From nose to tail, the Sea Otter is 27 to 64 inches long. The tail is 5 to 13 inches long.
Color: The sea otter's body is brown, with a light tan head, cheeks, and throat, and an even lighter belly.
Nose: Aspen leaf shaped. Females have a pink scar on their noses after mating.
Feet: Sea otters have strong, but very small, forepaws. The rear paws are so elongated and webbed that they are like flippers. The claws are semi-retractable.
 Hair: Very thick, silky, and sleek. The guardhairs are 1.3 to 1.4 inches long, and the underhairs are about 0.7 inches long.
Track/Sign: N/A

Food: Clams, mussels sea urchins, crabs, octopi, abalone. They do not tend to eat fish, though they certainly will if the opportunity arises (sea otters aren't the fastest critters ever).
Conservation Status: Endangered


Sea Otters are found primarily on the Pacific coast of North America. Some are also found on the coast of Russia and Japan. They live in and near kelp beds, which they rely on for both food and shelter. Most of their prey organisms feed on kelp or on other organisms that feed on kelp, and the kelp forests are a challenging habitat for large predators like Orcas. Sea Otters also use kelp beds literally as "beds". One of the unique challenges of living in the ocean is that it's always moving. To avoid drifting away from each other and their habitat, they often wrap themselves in kelp, which is sturdily anchored to the sea floor, before taking a nap.

Oil pollution is one of the primary threats to Sea Otters. Sea Otters are very sensitive to pollution. As well as being toxic if ingested, oil makes it impossible for them to keep their fur clean. Air bubbles trapped in their fur keep the otters from ever actually getting wet, allowing them to stay warm without the thick blubber layer that most marine mammals require. The oil forces the air bubbles out of the otters' fur and mats the fur to their bodies, eventually causing oiled otters to die of hypothermia. Fishing nets and the spread of infectious disease are also major threats to Sea Otters.

Sea Otters are also among the increasing number of animals known to use tools. They primarily eat shellfish, which are notoriously difficult to get into. Sea Otters get around this problem by taking a rock from the sea floor (some otters even have a favorite rock that they keep track of!) and using it to open the shellfish. An otter will place a rock on its stomach, and bash a clam or other shellfish on the rock until the shell is broken enough that they can eat the clam out of it. Otters also use rocks to bash abalone off of surfaces they are attached to on the sea floor. It's not surprising that some Sea Otters have favorite rocks, because every day they have to collect and eat enough shellfish to add up to 30% of their body weight. For the average otter, that's about 20 pounds of food per day! That's a lot of clams!

Sea Otter Pic! Pt. Defiance Zoo & Aquarium

Sea Otters at Point Defiance Zoo & Aquarium. © Chiara DeNeve

The impact of sea otters on kelp forests and potential incidental influence on climate change

Too much CO2 (carbon dioxide) in the atmosphere traps heat ( Climate Change- How do we know? ). Kelp "eats" (has a high rate of uptake of) atmospheric CO2. Sea urchins eat kelp (releasing CO2). Sea otters eat sea urchins.

See where this is going? ; )

The authors of is article (see: "Do trophic cascades affect the storage and flux of atmospheric carbon? An analysis of sea otters and kelp forests" ) combine sea otter research from the past 40 years, over their North American range, to look at the impacts that sea otters, due to their consumption of sea urchins, have on the health of kelp beds and as a result on the amount of atmospheric CO2, and the C (carbon) cycle.
Their findings?
"Although questions remain concerning the pathways and compartments of kelp C flux and storage, sea otters undoubtedly have a strong influence on these elements of the C cycle. Predator-induced trophic cascades likely influence the rates of C flux and storage in many other species and ecosystems."

In other words, the sea otters eating sea urchins helps to keep the population of sea urchins "in control", keeping them from eating so much kelp, which means that there is more kelp to "eat" more CO2, which means there is less CO2 bouncing around in the atmosphere!


Link to research:
"Do trophic cascades affect the storage and flux of atmospheric carbon? An analysis of sea otters and kelp forests" Christopher C Wilmers, James A Estes, Matthew Edwards, Kristin L Laidre, and Brenda Konar

       

 

Linking Up! Otter Connections.

Interested in more information about otters? Listed here for your convenience, links to additional sources of information> conservation, research, general information, etc. (This is not a complete listing, but it is a good start! ; ) 

*OtterQuest (includes a more complete listing of otter facilities, sites and resources) 

Governmental 
*IUCN Otter Specialist Group
^  The OSG Otter Blog
*Washington State Department of Fish &Wildlife
*New York State Department of Environmental Conservation 
*Illinois Department of Natural Resources
*Minnesota Department of Natural Resources
*Indiana Department of Natural Resources 

Research, Zoos, Aquariums, & Rehabilitation Facilities
*The International Otter Survival Fund (IOSF)
*Shedd Aquarium
*St. Louis Zoo
*Seattle Aquarium & Woodland Park Zoo
*Oregon Zoo  

Special Interest Groups
*OtterQuest
*Friends of the Sea Otter
*River Otter Alliance 
*Otternet 

Otters 'Round the World (an introduction to the otter 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 below for distribution of specific species.

 Currently eight of the species are experiencing a decline in populations. Five otter species are considered endangered, 3 are considered vulnerable (or near threatened), and only four of the species are listed in the category of "least concern" by the IUCN Otter Specialist Group.

Otter species status:	Status	Population Trend
Sea Otter ~ Enhydra lutris	Endangered	Stable
North American River Otter ~ Lontra canadensis	Least Concern	Stable
Neotropical Otter ~ Lontra longicaudis	Undetermineable	Decreasing
Marine Otter ~ Lontra felina	Endangered	Decreasing
South American River Otter ~ Lontra provocax	Endangered	Decreasing
Giant Otter ~ Pteronura brasiliensis	Endangered	Decreasing
Spotted-Necked Otter ~ Lutra maculicollis	Least Concern	Decreasing
Cape Clawless Otter ~ Aonyx capensis	Least Concern	Stable
Congo Clawless Otter ~ Aonyx congicus	Least Concern	Unknown
Eurasian Otter ~ Lutra lutra	Near Threatened	Decreasing
Hairy Nosed Otter ~ Lutra sumatrana	Endangered	Decreasing
Smooth Coated Otter ~ Lutrogale perspicillata	Vulnerable	Unknown
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 ~ Lutra maculicollis 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 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)