Tuesday, May 31, 2016

Neotropical Otter, Southern River Otter, and Marine Otter... the last 3 modern species *remaining* on the tree

The Neotropical Otter, Southern River Otter, and Marine Otter evolved from the line of the North American River Otter, while moving southward, to being uniquely adapted species in Central and South America.

Here's a quick peek at these otters!


Neotropical Otters (Lontra longicaudis) look very similar to North American River Otters and Southern River Otters. They get their *species name* (longicaudus which literally means *long tail*) from their looong tails! Their tail is over a third of their total body length.

They live in a wide range of habitats, from forested stream, lakes, temporary to permanent swamps/marshes, to marine environments. The Neotropical otter lives across most of Central and South America, from northern/central Mexico down to southern Argentina (primarily excluding Baja Mexico and northern Mexico *and* most of the western coast of South America).


Neotropical otters are *sexually dimorphic* (sexually dimorphic = differences in the species based on whether the critter is male or female). Males are about 25% larger than females, with males in some areas getting up to 70" (1.8 m) long and 55 lbs (25 kg).
Neotropicals are elusive (and rarely seen) and aren't generally social with each other, with the apparent exception being females with their cubs.


Neotropical otters, listed as "Near Threatened" by IUCN RedList, are considered to be at risk in some sections of it's range due to habitat degradation (due to pollution and habitat destruction)


The Southern River Otter (Lontra provocax), or South American River Otter, is found only in western Argentina and southern Chile. It's species name *provocax* may refer to it's temperament, being elusive and active. Through most of it's range it's found in freshwater; in parts of Chile though it also uses marine environments.


Females will live in family groups with their offspring, but adult males tend to be solitary.


Southern river otters are considerably smaller than Neotropical otters; growing up to ~48"(1.2m) long and weighing up to ~22 lbs (10 kg).
They are listed as "Endangered" by IUCN RedList. The population is really struggling, and is unfortunately expected to decline by over 50%, due to habitat destruction and human disturbance, over the next 30 years.


The Marine Otter (Lontra felina), also known as the Sea Cat (*felina* means *cat*), is found along the western coast of South America, from Peru south to the southern tip of Chile and across to Argentina. They live in marine environments.


Very little is known about these otters. Sometimes they're seen alone, sometimes in small groups. Offspring are seen with both parents for about the first 10 months, it's currently believed that the parents are monogamous.
The mothers are sometimes seen carrying young on their bellies, like sea otters.

Marine otters are the smallest marine mammal and second smallest of all of the otters, being up to ~ 44" (1.15 m) long and ~12 lbs (5 kg).
They are listed as "Endangered" by IUCN RedList.


Phylogenetic Tree of Otters

Monday, May 30, 2016

THE North American River Otter! (the oldest living Lontra ; )

The North American River Otter (Lontra canadensis) is the oldest living species in the Lontra (genus) lineage (see phylogenetic tree at the bottom of the page).

The North American river otter is the ONLY otter not to be listed as *declining* by the IUCN, and it is the only otter listed as "Least Concern" in the IUCN RedList, even though they were largely killed off, primarily due to over-hunting, by the early 1900s.
In many states where they were considered *extirpated* (extirpated= completely destroyed) they were re-established through a reintroduction program. They have been eliminated in parts of their range due to habitat damage and still face a lot of challenges to survival.
Currently North American river otters can be trapped in 14 of the 20 states where they were reintroduced; 14 US states and 4 Canadian states have no otter-take limits, unfortunately many of these states do not have up-to-date and/or ongoing research so measuring the actual sustainability of "harvest" is problematic at this time.

NorthAmerican River Otter. Photo: Chiara
North American river otters (NARO) are ~ 60" (1.5 m) long and weigh ~ 30 lbs (13 kg). 
They are found across almost all of North America, from the East Coast, through the Mid-West, across the North and South (including coastal regions), and throughout the West. They are missing, or largely missing throughout the SouthWest.
These otters are very adaptable and live in a wide variety of habitats including salt water, as long as they can get to fresh water to keep their fur clean.


So NARO that live along salt water coasts have to have access to fresh water also!


 


These otters can be fairly social, sometimes living alone and sometimes with social groups of adult female, offspring, and sometimes unrelated helpers AND groups of adult males (up to 17 individuals have been documented together!).
TODAY we saw a group of 6 sets of otter tracks together on a near shore island in Washington state.
We'd love to know what they were up to, we suspect snacking on some lovely crabs and clams!


Phylogenetic Tree!









Sunday, May 29, 2016

The most closely related otters: African Clawless and Congo Clawless Otters

The African Clawless Otter (Aonyx capensis) and the Congo Clawless Otter (Aonyx congicus) are very closely related, with some discussion over the years of whether they were actually the same species; additional genetics work is needed to really sort out the genetic divergence (distance) between the 2 species.
To get all science-geeky, most of the hair (fur) samples used have been so poorly preserved that getting genetic information from the samples is difficult, and getting fresh samples is very difficult because sampling (in other words catching) otters is *extremely* difficult in most areas.
Currently the genetics work that has been done (which is very limited) shows a 1.55% divergence between these 2 species... in a sequence that both of these otters show more than a 10% divergence with the other otters they have both been compared to... so that information seems *interesting*!

The African clawless otter (Aonyx capensis) is the 2nd largest freshwater otter (the Giant otter is the largest); it can be up to ~64" (1.6 meters) long and weigh ~80 lbs (36kg).

They are usually seen alone or in pairs, but are sometimes seen in groups up to 5 individuals.



The most widely distributed otter in Africa, the African clawless otter is found from South Africa up to Senegal and Ethiopa but is missing from the Congo basin where they are *replaced* by the Congo clawless otter. They are listed as "Near Threatened" by IUCN RedList.


Congo clawless otters (Aonyx congicus) are considered "rare or very rare" and are also listed as "Near Threatened" by IUCN RedList. They live in the central African regions of the Congo basin: Republic of Congo, Democratic Republic of Congo, Equatorial Guinea, Gabon, and portions of countries adjacent:  northern Angola, southern Cameroon, southern Central African Republic, Rwanda, Burundi, and Uganda. Due to possible mis-identification with the African clawless otter, scientists are is still a bit fuzzy on the Congo clawless' distribution.


It is hard to tell the African clawless and the Congo clawless apart in the wild. Both otters are very similar in size, color, and even in the structure of their feet. In the wild the most obvious difference seems to be that the Congo clawless otter has a ring of white fur surrounding the small dark patch of fur that both species have above their nose and between their eyes.

The Congo clawless otter is slightly smaller than the African clawless, it is ~62" (1.5 m) long and weighs ~75lbs (32 kg)


Very little is known about this otter, as they are rare, but they seem to be the most terrestrial species of otter.




Saturday, May 28, 2016

The most public and *most famous* otters: Asian Small-clawed Otter and Smooth-coated Otter




Asian Small-clawed Otters (Aonyx cinereus) are social and gregarious. They live in social groupings up to 15 members, believed to be family based around a pair that mate for life.
They have, as their name implies, very short claws on their fingers with nearly human dexterity (nimbleness), with limited webbing on their front paws. They use their *very* delicate sense of touch to catch prey.

Asian small-clawed otters are the smallest of all of the otters,  ~ 37" (95 cm) long and weighing ~13 lbs (5 kg). They have a *plumper* appearance than the rest of the otters, with a broad rounded head, and with very little difference between females and males. 



This otter has a large distribution range (the geographic area in which they live) across southeastern Asia: from India across to Palawan (the Philippines), Taiwan, and southern China.

This species is tolerant of imperfect conditions, and because of this are the otter species most commonly kept in captivity (zoos, aquariums, etc.). In their native range they have even been kept and trained as fishing companions, primarily for driving fish in to nets. Due to decreased fish stocks because of over-fishing from *modern* fishing techniques, like gill-netting, this practice is becoming less common. This also means that the habitat and food-sources for all of the otters in the area is being damaged/depleted. The Asian Small-clawed Otter is listed as "Vulnerable" in IUCN RedList.

Smooth Coated Otters (Lutrogale perspicillata) have also been trained as fishing companions in southeast Asia.


VIDEO! To see an example of otters assisting with net fishing, view this video from 9:13 to 11:00.
Video credited to and linked from Nature and Life, Episode #160 (via YouTube).
Cool vid guys, Thank you!





Smooth coated otters are up to ~51" (1.3 m) long and 25 lbs (12 kg) in weight. They have a velvety appearance because of their short dense fur and lean bodies.


The smooth-coated otter also lives in family groupings based on a monogamous mated pair. The alpha female (the female of the mated pair) is dominant over all of the other otters in the *romp* (romp = any group of otters, except sea otters which are called rafts when floating together in groups).

Even though they are the most common otter species in their range, the Smooth coated otter faces many of the same problems as the Asian small-clawed otter and is also listed as "Vulnerable" in IUCN RedList. Their distribution (where they live) ranges across much of southern and southeastern Asia, with a recent (and currently unknown) population in Iraq.

In 1960 a smooth coated otter from Iraq, Mijbil, became world famous when Gavin Maxwell published "Ring of Bright Water" (the novel was made in to a movie in 1969).




Phylogenetic Tree of The Otters:


Friday, May 27, 2016

Next up are the most common and the rarest: Eurasian & Hairy-nosed Otters

Developing from the same lineage as the Sea Otter and Spotted-necked Otter are the Lutra-type otters of the Lutra and Aonyx sub-branches. The oldest sub-branching and the 2 oldest extant (extant= currently living) otters in this group are the Eurasian Otter (Lutra lutra) and the Hairy-nosed Otter (Lutra sumatrana).

 The Eurasian Otter (Lutra lutra) is found throughout Europe, Asia, and in parts of northern Africa. It is the only otter living through much of its range, so it is rarely confused for any other animal. Despite being, for otters, habitat generalists (meaning that they live in a very wide variety of habitats)  and inhabiting a large geographical range, their populations continue to decline and are listed as "Near Threatened" by IUCN RedList


They are a very adaptable otter in habit and diet; they use both fresh and salt water areas but require access to fresh water so they can clean their fur.

Eurasian otters get up to ~56" (1.4 meters) long and ~26 lbs (12kg). They tend to live alone, except when mating or raising pups.

Hairy-nosed ottera (Lutra sumatrana) are found in southeastern Asia: Cambodia, Vietnam, Thailand, Indonesia, Malaysia, and possibly Burma. The populations are isolated and very vulnerable, and considered to be in rapid decline so they are listed as "Endangered" by IUCN RedList.



 The Hairy-nosed otter is believed to be rarest of all of the otters. The photo above was taken in captivity, of one of only 2 hairy-nosed otters held in *zoo* captivity.
Hunting and habitat degradation are it's biggest threats.

Hairy-nosed otters are smaller than Eurasian otters, generally to ~52" (1.3 m) long and 17 lbs (8kg).
Very little is known about their social activities, but it is believed that they are more social than Lutra lutra (Eurasian otter).




Thursday, May 26, 2016

Next on the phylogenetic tree: the Sea Otter and the Spotted-Necked Otter!

Let's start with that phylogenetic tree from the last post again...


... this tree is designed to generally demonstrate the time-frames that the otter species evolved from a common line over time (mya= million years ago) to the otter species we know today. Following the line of descendancy (like ancestry but the other way 'round ;) ) you can see that after the split that lead to the Giant Otter there is another evolutionary split that occurs in the Late Miocene, this split leads to the Lontra otters ~and~ *the rest* of the otter genera (genera= plural of genus).

The otters we are looking at today are included in *the rest* of the otter genera, but they are the next 2 oldest modern species: the Sea Otter and the Spotted-necked Otter.

The sea otter (Enhydra lutris) lives along the coastline of the northern Pacific and is the largest otter by weight, weighing up to ~100 lbs (46 kg). Topping out at ~5' (1.5m) long they are shorter and much stockier than the giant otter.

The sea otter rarely, if ever, leaves the ocean/estuary.
...but sometimes a female will haul out to give birth...
Bonus! Here is a video clip from Monterey Bay Aquarium of a wild sea otter that hauled out on a rock there to give birth (2016):


Sea otter populations were completely wiped out in many areas. The fur trade, beginning in the 1700s, drove the estimated population from near 300,000 down to ~1,000- 2,000 otters (in 13 otter colonies). The most stable populations of sea otters are currently in Russian: Kuril, Kamchatka, and Commander Islands.
It is listed "Endangered" on the IUCN RedList.

Enough about sea otters for the moment, what about the Spotted-necked Otter?

Want to get ALL science-geeky?!? Up until recently the spotted-necked otter was in the genus Lutra, but research done by Koepfli et al. (2008) and Sato et al. (2012) demonstrates that the spotted-necked otter should be in the genus Hydrictis.
So, the spotted-necked otter is now known, scientifically, as Hydrictis maculicollis!

Spotted-necked Otter (photographer:unknown, please contact with info)
Some spotted-necked otters have no spots at all, but for those that do, each one has unique markings.
They range up to ~42 inches (1m) long tip-to-tail and ~20 lbs (9kg) in weight.

They are found across central and southern Africa.

Spotted-necked water are very water oriented, not straying far from freshwater shorelines. So, while they have a large distribution (distribution in wildlife speak means "the geographical area in which teh species can be found") their dispersion (dispersion = pattern of distribution of individuals within a habitat) can be fairly low. What does this mean for this otter? It is very susceptible (at risk from) habitat destruction.

IUCN RedList lists them as "Near Threatened" due to habitat destruction/degradation.






Wednesday, May 25, 2016

The oldest otter in the world... the Giant Otter

 The Giant Otter (Pteronura brasiliensis) is the oldest living species of otter on Earth. It is believed to have evolved from an extinct genus, Satherium. The clade (definition= branch; in biology the term is used to refer to a group of animals that includes a common ancestor and all of it's descendants) that includes the giant otter split from the rest of the otter species ~5-11 million years ago.

The genetics is still being hammered out, but the following hopefully helps put the development of our modern otter species in to perspective!


The giant otter is the largest (longest) of the current otter species with some males getting over 7' (or 2 m) long (nose to end of tail) and weighing over 70 lbs (32 kg).

The giant otter is listed "Endangered" on IUCN's RedList.
It is very social and lives in the northern and central fresh water regions of South America in family groups up to 20 members (generally 3-10 though).

Research published recently even shows giant otters will mob jaguars!




World Otter Daze (Days May 25 - May 31)



Otters- 13 Extant Species


13 Otter Species
(extant= still in existence)
Location
Status
(via OSG and IUCN)
Population Trend
CITES Appendix
African Clawless Otter
Aonyx capensis
S. and Central Africa
Near Threatened
Decreasing
I
Asian Small-Clawed Otter
Aonyx cinereus
Southeast Asia
Vulnerable
Decreasing
II
Congo Clawless Otter,
Aonyx congicus
W. Central Africa
Near Threatened
Decreasing
I
Sea Otter,
Enhydra lutris
Coastal N. Pacific
Endangered
Decreasing
I (E. l. nereis)
II (E. l. lutris & kenyoni)
Spotted-Necked Otter
Hydrictis maculicollis
S. and Central Africa
Near Threatened
Decreasing
II
North American River Otter
Lontra canadensis
N. America
Least Concern
Stable
II
Marine Otter
Lontra felina
W. Coast S. America
Endangered
Decreasing
I
Neotropical Otter
Lontra longicaudis
Central and S. America
Near Threatened
Decreasing
I
South American River Otter
Lontra provocax
Southern S. America
Endangered
Decreasing
I
Eurasian Otter
Lutra lutra
Europe, Asia, N. Africa
Near Threatened
Decreasing
I
Smooth-Coated Otter
Lutrogale perspicillata
Southern Asia
Vulnerable
Decreasing
II
Hairy-Nosed Otter
Lutra sumatrana
Southeast Asia
Endangered
Decreasing
II
Giant Otter
Pteronura brasiliensis
N. andCentral S. America
Endangered
Decreasing
I
 

The Phylogenetic Tree of the 13 Species of Extant (extant= still living) Otter Species!

Tuesday, May 24, 2016

Rise Up and Grab your Towel! (May 25 aka Day of The Lilac Towel ; )



Lilac Day aka "The Glorious 25th of May"
Towel Day

Lilac Day and Towel Day commemorate and celebrate the lives of Douglas Adams ("The Hitchhiker's Guide to the Galaxy" => Towel Day) and Terry Pratchett (the "Discworld" series => The Glorious 25th of May), authors that reflected human nature back to us in ways both insanely entertaining and incredibly insightful.

I'm not enjoying writing this; I'm trying to find the balance between the joy they've both brought to me (and sooo many other people) and sadness that they are gone too soon.

Lilac Day (also known as The Glorious 25th of May) is a day that Pratchett fans wear lilac to honor all those who struggle with Alzheimer's disease and comes from the tradition, in Discworld, of a select few who wear the lilac to honor those that went beyond the call of duty/those that fell during the uprising of the Glorious Revolution of Treacle Road:
 "But here's some advice, boy. Don't put your trust in revolutions. They always come around again. That's why they're called revolutions."

You want more?

"  “No! Please! I'll tell you whatever you want to know!" the man yelled.
"Really?" said Vimes. "What's the orbital velocity of the moon?"
"What?"
"Oh, you'd like something simpler?”  "

Hmmm... more?!?

"  "That's a nice song," said young Sam, and Vimes remembered that he was hearing it for the first time.
"It's an old soldiers' song", he said.
"Really, sarge? But it's about angels."
Yes, thought Vimes, and it's amazing what bits those angels cause to rise up as the song progresses. It's a real soldiers' song: sentimental, with dirty bits.
"As I recall, they used to sing it after battles", he said. "I've seen old men cry when they sing it", he added.
"Why? It sounds cheerful."
They were remembering who they were not singing it with, thought Vimes. You'll learn. I know you will.  "

Want to know more? Go! Read "Night Watch"! (wikilink) ... or any of Pratchett's novels (41 in the Discworld series alone)

Towel Day honors Douglas Adams and ALL of his creative endeavors; why the towel?
"  A towel, it says, is about the most massively useful thing an interstellar hitchhiker can have. Partly it has great practical value. You can wrap it around you for warmth as you bound across the cold moons of Jaglan Beta; you can lie on it on the brilliant marble-sanded beaches of Santraginus V, inhaling the heady sea vapours; you can sleep under it beneath the stars which shine so redly on the desert world of Kakrafoon; use it to sail a miniraft down the slow heavy River Moth; wet it for use in hand-to-hand-combat; wrap it round your head to ward off noxious fumes or avoid the gaze of the Ravenous Bugblatter Beast of Traal (such a mind-bogglingly stupid animal, it assumes that if you can't see it, it can't see you — daft as a brush, but very very ravenous); you can wave your towel in emergencies as a distress signal, and of course dry yourself off with it if it still seems to be clean enough.  "

Still not clear?!? Go, find a copy and read it!!! (wikilink)

My favorite book by Douglas Adams, oddly, isn't one of his novels... it's "Last Chance to See", which is both a BBC radio series (1989) and a book (1990), co-written by Mark Carwardine. "Last Chance to See" is a personal exploration by the authors of the ecological issues that face endangered species around the world.

My favorite book by Terry Pratchett? Whichever one I happen to have on my nightstand! ;)