SQUIRRELS: SHADOW TAILS

One of the little animals I see daily in Kitsilano, Vancouver, are the very busy, highly comic rodents we know as squirrels. 

They spend their days busily gathering and caching food and their nights resting from all that hard work. 

My neighbourhood has mostly Eastern Gray squirrels, Sciurus carolinensis (Gmelin, 1788) who come in a colour palette of reddish-brown, grey (British spelling) and black. 

These cuties have bushy tails and a spring in their step — racing around gathering nuts, finding secret hiding spots to cache them, teasing dogs and generally exuding cuteness.

We find the first fossil evidence of tree squirrels in the Pleistocene. At least twenty specimens have been found of Sciurus carolinensis in Pleistocene outcrops in Florida on the eastern coast of the United States. Over time, their body size grew larger then shrunk down to the 400 to 600 g (14 to 21 oz) weight we see them today.  

Eastern Gray squirrels have two breeding seasons in December-January and June-July. This past year was warm. On Vancouver Island, the Eastern Grays bred again in early September. One wonders if the heat dome killed off the July litter, and with the return of more favourable weather, the parents have been induced to breed again.

While they are not native to Vancouver, they are plentiful. They were introduced to the region over a hundred years ago and have been happily multiplying year upon year. 

Our native species are the smaller, reddish-brown, rather shy Douglas squirrels, Tamiasciurus douglasii (Bachman, 1839), and the nocturnal Northern Flying Squirrels, Glaucomys sabrinus (Shaw, 1801).  

Sciurus, is derived from two Greek words, skia, meaning shadow, and oura, meaning tail. The name choice is poetic, alluding to squirrels sitting in the shadow of their tails. 

The specific epithet, carolinensis, refers to the Carolinas on the eastern seaboard of the United States, an area that includes both North and South Carolina. It was here that the species was first recorded and still rather common. In the United Kingdom and Canada, Sciurus carolinensis is referred to as the Eastern Gray or grey squirrel — and though adorable is an invasive species. 

In the United States, Eastern is used to differentiate the species from the Western Gray or Silver-Gray squirrel, Sciurus griseus, (Ord, 1818). 

The Ord here, of course, is George Ord, the American zoologist who named the species based on notes recorded by Lewis and Clark in the early 1800s. If you fancy a read, check out his article from 1815, "Zoology of North America." It is charming, anachronistic and the first systemic zoology of America by an American. 

In the Kwak̓wala language of the Kwakwaka'wakw First Nation, speakers of Kwak'wala, of the Pacific Northwest, we use the word ta̱minasux̱, to say: "that is a squirrel." 

The word for shadow in Kwak'wala is gagumas and tail is ha̱t̕sa̱x̱ste' — so I will think of these wee wonders of the Order Rodentia in the family Sciuridae as the Gagumas ha̱t̕sa̱x̱ste' of Khahtsahlano. 

SQUIRRELS: SHADOW TAILS

One of the little animals I see daily in Kitsilano, Vancouver, are the very busy, highly comic rodents we know as squirrels. 

They spend their days busily gathering and caching food and their nights resting from all that hard work. 

My neighbourhood has mostly Eastern Gray squirrels, Sciurus carolinensis (Gmelin, 1788) who come in a colour palette of reddish-brown, grey (British spelling) and black. 

These cuties have bushy tails and a spring in their step — racing around gathering nuts, finding secret hiding spots to cache them, teasing dogs and generally exuding cuteness.

We find the first fossil evidence of tree squirrels in the Pleistocene. At least twenty specimens have been found of Sciurus carolinensis in Pleistocene outcrops in Florida on the eastern coast of the United States. Over time, their body size grew larger then shrunk down to the 400 to 600 g (14 to 21 oz) weight we see them today.  

Eastern Gray squirrels have two breeding seasons in December-January and June-July. This past year was warm. On Vancouver Island, the Eastern Grays bred again in early September. One wonders if the heat dome killed off the July litter, and with the return of more favourable weather, the parents have been induced to breed again.

While they are not native to Vancouver, they are plentiful. They were introduced to the region over a hundred years ago and have been happily multiplying year upon year. 

Our native species are the smaller, reddish-brown, rather shy Douglas squirrels, Tamiasciurus douglasii (Bachman, 1839), and the nocturnal Northern Flying Squirrels, Glaucomys sabrinus (Shaw, 1801).  

Sciurus, is derived from two Greek words, skia, meaning shadow, and oura, meaning tail. The name choice is poetic, alluding to squirrels sitting in the shadow of their tails. 

The specific epithet, carolinensis, refers to the Carolinas on the eastern seaboard of the United States, an area that includes both North and South Carolina. It was here that the species was first recorded and still rather common. In the United Kingdom and Canada, Sciurus carolinensis is referred to as the Eastern Gray or grey squirrel — and though adorable is an invasive species. 

In the United States, Eastern is used to differentiate the species from the Western Gray or Silver-Gray squirrel, Sciurus griseus, (Ord, 1818). 

The Ord here, of course, is George Ord, the American zoologist who named the species based on notes recorded by Lewis and Clark in the early 1800s. If you fancy a read, check out his article from 1815, "Zoology of North America." It is charming, anachronistic and the first systemic zoology of America by an American. 

In the Kwak̓wala language of the Kwakwaka'wakw First Nation, speakers of Kwak'wala, of the Pacific Northwest, we use the word ta̱minasux̱, to say: "that is a squirrel." 

The word for shadow in Kwak'wala is gagumas and tail is ha̱t̕sa̱x̱ste' — so I will think of these wee wonders of the Order Rodentia in the family Sciuridae as the Gagumas ha̱t̕sa̱x̱ste' of Khahtsahlano. 

SQUIRRELS: SHADOW TAILS

One of the little animals I see daily in Kitsilano, Vancouver, are the very busy, highly comic rodents we know as squirrels. 

They spend their days busily gathering and caching food and their nights resting from all that hard work. 

My neighbourhood has mostly Eastern Gray squirrels, Sciurus carolinensis (Gmelin, 1788) who come in a colour palette of reddish-brown, grey (British spelling) and black. 

These cuties have bushy tails and a spring in their step — racing around gathering nuts, finding secret hiding spots to cache them, teasing dogs and generally exuding cuteness.

We find the first fossil evidence of tree squirrels in the Pleistocene. At least twenty specimens have been found of Sciurus carolinensis in Pleistocene outcrops in Florida on the eastern coast of the United States. Over time, their body size grew larger then shrunk down to the 400 to 600 g (14 to 21 oz) weight we see them today.  

Eastern Gray squirrels have two breeding seasons in December-January and June-July. This year has been unseasonably warm. On Vancouver Island, the Eastern Grays bred again in early September. One wonders if the heat dome killed off the July litter, and with the return of more favourable weather, the parents have been induced to breed again.

While they are not native to Vancouver, they are plentiful. They were introduced to the region over a hundred years ago and have been happily multiplying year upon year. 

Our native species are the smaller, reddish-brown, rather shy Douglas squirrels, Tamiasciurus douglasii (Bachman, 1839), and the nocturnal Northern Flying Squirrels, Glaucomys sabrinus (Shaw, 1801).  

Sciurus, is derived from two Greek words, skia, meaning shadow, and oura, meaning tail. The name choice is poetic, alluding to squirrels sitting in the shadow of their tails. 

The specific epithet, carolinensis, refers to the Carolinas on the eastern seaboard of the United States, an area that includes both North and South Carolina. It was here that the species was first recorded and still rather common. In the United Kingdom and Canada, Sciurus carolinensis is referred to as the Eastern Gray or grey squirrel — and though adorable is an invasive species. 

In the United States, Eastern is used to differentiate the species from the Western Gray or Silver-Gray squirrel, Sciurus griseus, (Ord, 1818). 

The Ord here, of course, is George Ord, the American zoologist who named the species based on notes recorded by Lewis and Clark in the early 1800s. If you fancy a read, check out his article from 1815, "Zoology of North America." It is charming, anachronistic and the first systemic zoology of America by an American. 

In the Kwak̓wala language of the Kwakiutl or Kwakwaka'wakw, speakers of Kwak'wala, of the Pacific Northwest, use the word ta̱minasux̱, to express: "that is a squirrel." 

The word for shadow in Kwak'wala is gagumas and tail is ha̱t̕sa̱x̱ste' — so I will think of these wee wonders of the Order Rodentia in the family Sciuridae as the Gagumas ha̱t̕sa̱x̱ste' of Khahtsahlano. 

FURRY KAMIKAZE PILOTS: FLYING TREE SQUIRRELS

Mammals can walk, hop, swim and fly; a few, like marsupial sugar gliders, can even glide. 

With 52 species scattered across the Northern hemisphere, flying squirrels are by far the most successful group that took to the skies.

While not true flyers per se, these wee marsupials know how to skedaddle, coasting from tree to tree one giant leap of faith at a time. 

And they are pretty cute if you look past their teeth and claws. Think adorable kamikaze pilot snugged inside a paper aeroplane with just enough Freddie Kruger to keep it interesting.

Their airborne manoeuvres are made possible by a half-plane, half-parachute body design — a bat-suit style membrane that puffs up into a parachute their feet and hands. They have evolved teensy but sturdy wrists strong enough to support long cartilaginous rods, making their personal brand of flight possible. Their wee specialized wrist bones are a distinctive feature as they do not share them with their non-flying brethren. 

The origin of flying squirrels is a point of contention: while most genetic studies point towards the group splitting from tree squirrels about 23 million years ago, the oldest remains – mostly cheek teeth – suggest the animals were already soaring through forests 36 million years ago. 

Troublesome are the findings from studies that show the dental features used to distinguish between gliding and non-gliding squirrels may actually be shared by the two groups.

In 2002, the digging of a dumpsite in Barcelona, Spain unearthed a peculiar skeleton. As the bones were extracted one by one they found first a tail, then two thigh bones — big enough that they initially thought they might belong to a small primate. 

Once they were all removed and re-articulated, you could see that they belonged to a rodent. 

As the specimen was being prepared and the associated matrix screen-washed for loose bits, they discovered the wee wrist bones. From the mud emerged the minuscule specialized wrist bones that confirmed this was the skeleton of Miopetaurista neogrivensis, an extinct flying squirrel.

Fossil flying squirrel Miopetaurista neogrivensis

Casanovas-Vilar et al. described the 11.6 million years old Spanish fossil — the oldest squirrel ever found. The wrist bones reveal that the animal belongs to the group of flying squirrels that have large sizes. 

Evolutionary analyses — the sexy science combining molecular and paleontological data — told a new story, flying squirrels evolved from tree squirrels as far back as 31 to 25 million years ago, and possibly even earlier. 

We also confirmed that Miopetaurista is closely related to Petaurista, a modern group of giant flying squirrels. 

Their skeletons are so similar, in fact, that the large extant species that inhabit the tropical and subtropical forests of Asia today should be considered living fossils.

Molecular and paleontological data are often at odds, but this fossil shows that they can be reconciled and combined to retrace history. 

There is still more to be done to tease out the lineage of these gliding mammals. Discovering older fossils, or even transitional forms could help to retrace how flying squirrels took a leap from the rest of their evolutionary tree.

Flying squirrels are the only group of gliding mammals with remarkable diversity and a wide geographical range. However, their evolutionary story is not well known. Thus far, the identification of extinct flying squirrels has been exclusively based on dental features, which, contrary to certain postcranial characters, are not unique to them. 

While best efforts are made, fossils attributed to this clade may indeed belong to other squirrel groups. The oldest fossil skeleton of a flying squirrel (11.6 Ma) displays the gliding-related diagnostic features shared by extant forms and allows for a recalibration of the divergence time between the tree and flying squirrels. 

Phylogenetic analyses combining morphological and molecular data generally support older dates than previous molecular estimates (~23 Ma), being congruent with the inclusion of some of the earliest fossils (~36 Ma) into this clade. They also show that flying squirrels experienced little morphological change for almost 12 million years.

Image: The fossil flying squirrel Miopetaurista neogrivensis

(a) Reconstruction of the skeleton based in the partial skeleton IPS56468 from Abocador de Can Mata. Missing elements are based on extant giant flying squirrel Petaurista petaurista and are coloured in blue. 

https://doi.org/10.7554/eLife.39270.001 / https://doi.org/10.7554/eLife.39270.002

SQUIRREL: TAMINASUX

Eastern Grey Squirrel, Sciurus carolinensis

One of the little animals I see daily are the very busy, highly comic rodents we know as squirrels. They spend their days gathering food and their nights resting from all their hard work. 

My neighbourhood has mostly Eastern grey squirrels, Sciurus carolinensis (Gmelin, 1788) who come in a colour palette of reddish-brown, grey and black. 

These cuties have bushy tails and a spring in their step — racing around gathering nuts, teasing dogs and generally exuding cuteness.

We find the first fossil evidence of tree squirrels in the Pleistocene. 

At least twenty specimens have been found of Sciurus carolinensis in Pleistocene outcrops in Florida on the eastern coast of the United States. Over time, their body size grew larger then shrunk down to the 400 to 600 g (14 to 21 oz) weight we see them today.  

Eastern grey squirrels have two breeding seasons in December-January and June-July. This year has been unseasonably warm. On Vancouver Island, the Eastern Greys bred again in early September. One wonders if the heat dome killed off the July litter, and with the return of more favourable weather, the parents have been induced to breed again.

While they are not native to Vancouver, they are plentiful. They were introduced to the region over a hundred years ago and have been happily multiplying year upon year. 

Our native species are the smaller, reddish-brown rather shy Douglas squirrels and the nocturnal Northern Flying Squirrels.  

Shadow tails — Sciurus, is derived from two Greek words, skia, meaning shadow, and oura, meaning tail. The name choice has a certain poetic appeal. It alludes to squirrels sitting in the shadow of their tails. I prefer to think of it as meaning something closer to stealth ninja — but that's just me. 

The specific epithet, carolinensis, refers to the Carolinas on the eastern seaboard of the United States, an area that includes both North and South Carolina. It was here that the species was first recorded and still rather common. In the United Kingdom and Canada, Sciurus carolinensis is referred to as the Eastern grey or grey squirrel — and though adorable is an invasive species. In the United States, eastern is used to differentiate the species from the Western Gray or Silver-Gray squirrel, Sciurus griseus, (Ord, 1818). 

The Ord here, of course, is George Ord, the American zoologist who named the species based on notes recorded by Lewis and Clark in the early 1800s. If you fancy a read, check out his article from 1815, "Zoology of North America." It is charming and anachronistic in equal parts and the first systemic zoology of America by an American. 

In the Kwak̓wala language of the Kwakiutl or Kwakwaka'wakw, speakers of Kwak'wala, of the Pacific Northwest, use the word ta̱minasux̱, to point out that "that is a squirrel." 

The word for shadow in Kwak'wala is gagumas and tail is ha̱t̕sa̱x̱ste' — so I will think of these wee wonders of the Order Rodentia in the family Sciuridae as Gagumas ha̱t̕sa̱x̱ste' of Khahtsahlano.