Sunday, 19 January 2014

Bristol snakes 9: Northern Pine Snake

Northern Pine Snake
The last of Bristol Zoo’s snakes I will post about in this series is the impressive Northern Pine Snake Pituophis melanoleucus. These are some of the largest snakes in North America, and can grow as thick as my wrist and nearly 2m long.

With a range all over the southern part of North America, the various species (currently 5) of Pituophis are well known wherever they occur. Also known as bull snakes or gopher snakes (the last from one of their favourite prey items), all Pituophis are animals of dryer habitats, usually open woodland of either deciduous or coniferous forest with a suitable supply of prey. Despite their name, pine snakes are not confined to pine woodland, but also occurs in agricultural fields, brushland, and scrub. The range of the P.melanoleucusextends over most of the south eastern USA, with most of the population occurring from South Carolina around to Missisippi. With such a large range and flexibility in habitats, the species is doing reasonably well and is classed by the IUCN as Least Concern, although housing development and changes in farming have probably had some impact.

Northern Pine Snakes are typical constrictors, with a large range of prey items in which rodents feature heavily, although they will also climb trees and raid nests for young birds or even eggs. In defence against this nest raiding habit, one bird of pine woodlands, the rare and specialised Red-Cockaded Woodpecker Picoides borealishas developed a unique strategy. It makes its nest in living pine trees infected with a fungal disease called red heart rot, and surrounds the main nest cavity with resin wells which it keeps open so they bleed resin down the trunk around the nest. This means that any snake trying to climb the tree and reach the eggs or young will instead have to pass the sticky, distasteful resin first, thus discouraging the predators.
Red-Cockaded Woodpecker
Of course, Pine snakes themselves have predators, especially when young. Typical animals that might take them include raccoons, foxes, birds of prey, and quite possibly bears. The feral pigs now common across the southern US will also take them, and also root up and eat their eggs if they find them, and since there an estimated 2 – 4 million feral pigs in North America the ecological impact is devastating, although the Pine Snake at least seems to be holding its own.

Pine snakes are egg-layers, producing a clutch of up to 24 (usually less) eggs between June and August in a burrow or under rocks. Eggs hatch after around 70 days, and the young are quite large at birth, being up to 45cm long. At that stage they are already well able to take care of themselves, and will commence feeding on small rodents. They will usually be large enough to breed when around 3 years old. In captivity, the longest reported lifespan I have found is 22 years, but for most individuals around 15 is probably more typical.

Captive care for these snakes is similar to that for a Corn Snake, except scaled up because of their greater size and power.  For this reason they are not beginners snakes, as handling a full grown Pine Snake is definitely a job for an adult – they can be quite active and you need to know how to handle snakes to do it properly.

Next week, a new series starts – watch this space:

(images from wikipedia)

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