The scientific community refers to the red squirrel as Sciurus vulgaris, which in layman’s terms describes it as a common squirrel. However, Britain’s red squirrel population seems to be quite the opposite, only small pockets of these squirrels remain in the country. For some UK residents red squirrel sightings may be infrequent, whilst it’s grey equivalent is most abundant.
From the countryside to inner city they are common. Yet in 1788 German scientist Johann Friedrich Gmelinthe named the grey squirrel; Sciurus carolinensis, which translates as a squirrel from the US states of North and South Carolina. This being said squirrels rarely conform to the naming conventions applied to them and as such, the British landscape is now mostly absent of a truly enigmatic species.
The red squirrel is a small tree rodent clad in soft red-copper fur, with tufted ears and twinkling black eyes, its appearance alone may melt the heart of any observer. For conservation scientists public reverence and appreciation may be an important factor when aiming to amend the challenges. Popular animals capture the general public’s imagination and generate the most support towards conservation. They supply the money for environmental repairs and breeding programs and additionally drive the process encouraging action, further generating interest.
Dotted across Britain, reserves have been established to cradle the few reds that remain. Populations in some cases live within a conservation bubble of sorts, with grey squirrels kept from the area and their diet supplemented in times of need. Even with free rein to grow, the effect of the grey squirrel still permeates their refuge in the form of a virus. Whilst efforts were made to protect and isolate the red squirrels; open environments are fluid, dynamic and unpredictable, pathogens can easily slip under the radar.
In this case the virus in question is squirrel pox, grey squirrels are often attributed as the source of this infection, yet adversely to red squirrels they are capable of carrying the pathogen without succumbing to the symptoms. As prolific grey populations spread, expansion has been aided by its pox virus clearing away its competition. So effective is this method it may be observed in our own human history within the first conquests of the Americas.
With such an uphill journey for the red squirrels it raises questions about the effectiveness of the conservation methods in place, especially after an increase of pox occurrences in 2008. In some instances human intervention may go so far, with some populations reduced by up to 90% even with great public support this species needs to adapt or remain in a perpetual state of uncertainty. One area that saw a large percentage of squirrels succumbing to pox was within the coastal reserve at Formby, Merseyside. Yet scientists have begun to encounter examples in this area and others which strongly suggest red squirrels are capable of surviving this, finding the first promising signs of recovery. There may be strong evidence surviving a single exposure may be the start, in some individuals, antibodies have been observed, immunity to the virus might render squirrel pox reduction. Without antibodies a pathogen may repeatedly enter a biological system reproducing, unrestrained by an unaware immune system. The production of squirrel pox specific antibodies is an adaptation in progress, a process which may take generations yet its benefits may be witnessed fairly quickly.
Whilst the hereditary aspect of immunity might insure the long term survival of a population, it is monumentally slow. Luckily for squirrels their mammalian nature affords it a method of passing on immunity to its young without the need of passing on genetic protection. All mammals suckle their young, primarily this is seen as a food source, yet the milk has several properties; one component called colostrum contains copies of the mothers antibodies which may be absorbed and used by the young. This acts as a method of temporary immunisation, offering much needed protection when they are most fragile.
How might the red squirrel’s natural ability to adapt and thrive further their life span?