I smell a rat

16th July, World Snake Day

The region of southern Ontario where I was lucky enough to be able to stay for a couple of weeks in the first half of July holds an important yet threatened population of the Gray Ratsnake, Pantherophis spiloides. While participating in the memorable BIOSPHERE Youth Environmental Leadership Expedition at the Queen’s University Biological Station (QUBS) on the shores of Lake Opinicon, the enthusiastic program leader Dr. Shelley Ball interrupted our dinner one evening with a Gray Ratsnake she had just hand-caught. Perhaps one of the few things I will stop dinner for!

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Gray Ratsnake being held by Shelley

Gray Ratsnakes are one of Canada’s largest snakes. They are the largest in terms of length, with adult able to reach over six feet from head to tail, but are pipped by Bullsnakes with regard to mass.

During the expedition at QUBS, we were treated to a short presentation by Matt and Meg who are working on how to prevent the decline of this sizeable snake. One of the leading causes of fatalities in this species is road collisions. The dark colouration of the ratsnakes means that they are often mistaken for the shadows of overhead branches on roads, and are therefore not noticed by motorists. Even when they are recognised as snakes drivers have a hard time avoiding them, as due to their length they can easily stretch across the entire width of the road.

On account of this, Matt and Meg are working on avoiding these snake RTAs by reducing the incidences of snakes crossing the road. They are helping to develop snake-proof fences which aim to guide the snakes to specially-built culverts which they can use to get to the other side of the road without risking being hit. Gray Ratsnakes are semi-arboreal and spend lots of their time in trees, so are adept climbers. The fences to be implemented, therefore, need to be resistant to climbing by these agile snakes. Creating fences that not even ratsnakes can ascend also prevents a wide variety of other wildlife such as turtles from being hit and allows them to utilise the culverts as well.

Gray Ratsnakes are remarkably docile and are rarely aggressive when handheld. When threatened they do possess the abilility to release the contents of the cloaca, musking the assailant with a foul smell. However, the related Northern Water Snake behaves in this manner with far greater regularity. It, like the Gray Ratsnake, is non-venomous, so has to make itself as unappealing to predators as possible, by releasing both musk and excrement. Despite the lack of venom, the bites are still painful and the saliva of the Northern Water Snake has an anticoagulant which causes the bite to bleed more freely. However, although it might sound threatening, the water snake is another fascinating reptile.

I had the good fortune of glimpsing a Northern Water Snake on one occasion at QUBS as it swam past the boathouse. As its name suggests, it is a very strong swimmer. It will take sleeping fish at night in shallow water and during the day it will hunt other prey such as crayfish and amphibians among vegetation at the water’s edge.

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Northern Water Snake snaking through the water at the QUBS boathouse

To finish off this post for World Snake Day, I’ll mention the third species of snake we encountered on our expedition at QUBS, which was also the most numerous. The Common Garter Snake is, as its name suggests, frequent, but also fairly skittish. As a result, they are difficult reptiles to photograph. However, nearing the end of the expedition we disturbed one from a pile of dead leaves near the library. It retreated to a stone wall, from which it poked its head out to survey the scene, giving a rare opportunity to photograph this species.

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A curious Common Garter Snake.

The Common Garter Snake, like all but one snake in Ontario, is another non-venomous species. Snakes are often misrepresented as being solely dangerous creatures. However, less than a fifth of the world’s snake species are considered a threat to human health, with very few venomous snakes being found in the more populated temperature regions of the world. Instead of being feared, snakes should be more appreciated for their incredible diversity and fascinating range of habits.

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Apples on sticks

Yesterday the south-east group of the British Bryological Society visited the town of Wadhurst in the far east of Sussex, near Tunbridge Wells. A variety of habitats including streams, woodland, grassland and ditches led to an array of moss and liverwort species being recorded. All were new for the area as this was a place no bryologist had dared to tread before.

Highlights included my favourite liverwort, the large and fragrant Conocephalum conicum (Great Scented Liverwort), as well as non-bryophytes such as two new plant species for me – Orpine and Soft Shield Fern – and a new carabid in the form of Carabus monilis with its bronze lustre. However, apparently the best find of the day was one of mine. This was the apple-moss, Bartramia pomiformis.

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Bartramia pomiformis

This moss immediately struck me, growing on a sandy bank on the edge of a narrow lane. The patch was almost perfectly circular, a richer green than the surrounding winter vegetation. And it was easy to see how it got its name, from the rounded apple-like capsules.

These capsules, that many mosses have in some form or another, form the final stage in the life cycle of a moss. The capsules contain the spores. Like a fruit, the capsules darken with maturity, starting off green such as these but soon becoming dry and brown with age, at which point the spores will be released.

These spores, upon germination, will then grow into a protonema, which will develop into a sheet of felt-like rhizoids, from which the gametophore will arise. The gametophore will be the stage of a moss that many people will be familiar with. It is the typical plant-like form, with stems and leaves, resembling a flowering plant although without vascular structure. This means that mosses lack the transport systems that vascular plants use to transport water, nutrients and minerals to their cells through tubes such as the xylem and the phloem.

Mosses can be dioicous or monoicous. Dioicous mosses have the male and female reproductive organs on different individual gametophores, while monoicous mosses have both sex organs on the same plant. In both cases, the sperm from the male sex organ will be transported to the female sex organ by a drop of water, which is one reason why there is a higher density of moss species in wetter climates such as the Atlantic rainforests of western Scotland and Ireland.

Once fertilisation takes place, a sporophyte begins to emerge from the venter, where the embryo develops. Over a period of many months, a seta (stalk) will grow, on top of which a capsule will be produced. Eventually this will release spores, and the cycle will repeat itself.

When diving into the life cycles of many taxonomic groups, I am often amazed by the complexity behind what appear to be fairly simple organisms at a cursory glance.

Cell Rap!

My name is James

And I love all cells

There’re animal and plant cells

‘N’ I think they’re swell!

 

Both types have a nucleus

That stores the DNA

It also helps to make protein

And control its ev’ry way.

 

Chloroplasts are clever

And only plant cells have ‘em

They help in photosynthesis

And the plant’ll die without ‘em!

 

Starch grains are very useful

And unique to only plants

The membrane decides what’s in and out

And helps both animals ‘n’ plants

 

Cytoplasm is jelly-like

And the site of all reactions

Now let’s move on to more cell parts

My favourite plan of action!

 

All plant cells have a wall

To help keep the cell’s structure

It also seems to save the cell

From a devastating fracture

 

The vacuole is vital

‘Cos it helps to keep its shape

It also has a special sap

And resembles a tiny grape!