The Mole

David Beeson, March 2022

I could have started with a question: Which mammal is often around us, yet we seldom see? Because it is true. I have moles in the garden, they tunnel through the flowerbeds, under the lawn and, this winter, ploughed up chunks of our wildflower meadows, yet I’ve not seen one in years. I watch as they throw up diggings as they re-tunnel, but I do not see their velvet black body, chunky front limbs and small eyes. A female often builds her breeding nest near the house, but she keeps hidden.

The mole, Talpa europaea is present throughout England, Scotland and Wales but absent from the island of Ireland. It spreads through Europe to middle Russia and south to northern Greece, but is not found in much of Spain or Italy – where possibly the ground is too hot or dry for them.

You’ll know if a mole is around by its molehill excavations or by the lifting of turf as it burrows just below the surface. But such features are only temporary, and the molehills are washed back onto the soil surface with time and surface tunnels crushed by animals’ feet or chunky lawnmowers. With soils drying and hardening in the summer, most molehills are generated over the damper, cooler times of the year.

Tunnels do not only occur near the soil surface. Others will be much deeper and can be used to find food when soil invertebrates are driven deep by soil dryness.

The mammal occurs even in wet pasture, where larger molehills occur. Dog owners tell me that here their pets do catch surface moles there, presumably the animals are driven up by the flooding of their tunnels.

To survive on an adequate diet of worms and soil invertebrates our mole will need a permanent set of tunnels that function as traps, so colonising new land is easier from an established territory. Merely releasing a captured animal onto fresh land will kill it, as there will be no tunnel system it can adopt. No extensive tunnels equals no food.

To many a person’s surprise, moles are frequent in woodland with sufficiently deep soil, and are found on sand dunes and moorland but in lower densities. They are solitary with males 150% the weight of females.

Moles often have three periods of activity during a day each lasting three to four hours, but less if food is abundant. The mammals traverse their tunnel system looking for food that has stumbled into the system. When they dig they are not actively searching for food; they are merely extending their territory.

Breeding occurs in spring with births in late April in Southern England. Litters of 3- 4 are usual. Juveniles disperse within 6 weeks and have to search out their own territory – causing a high mortality.

In my garden, Talpa europaea are hunted by weasels underground, although any dispersing above ground may be taken by many predators. On local cricket grounds they are killed by the groundsmen and dead moles can sometimes be seen tied to fences. Poison is not legal, but tunnel traps are often set. In my early days, I attempted to disperse garden moles with a sonic system and smelly tunnel inserts. It did not work, and I settled down to let them live alongside us.

A three-year-old mole is doing well but some survive to reach six years.

The design of a mole is probably well known, yet their physiology to survive underground with limited oxygen is interesting. You will know that there are different types of haemoglobin – the oxygen-carrying element of red blood cells. Some can fully absorb oxygen at low concentrations – useful for either living high in the mountains or below ground in poorly ventilated spaces. This is how moles survive in such a hostile oxygen environment. Their bodies also are much more tolerant of high carbon dioxide levels – certainly levels that would kill me.

Moles can be positive in a garden opening up air and drainage channels.

Having caught a few live moles, I’m aware of their strong digging ability and high-pitched squeak when held. Yet, despite needle-sharp canine teeth, I have never been bitten.

We now occasionally complain about our moles, while leaving them to live their lives around us. We quietly ignore each other. Try to do the same.

Home page is: http://www.nwhwildlife.org.

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