The Urban Pantheist

Is it a shame that Boston's biggest and most beautiful slug is a Eurasian alien? Perhaps, I've been unable to summon anything but positive feelings for the leopard slug Limax maxima since I first encountered one on Mission hill 27 years ago. Apparently restricted to urban areas and reaching an adult stretched length of 4 inches, the leopard slug deserves a place as a sports team mascot like it's cousin the western banana slug.


I got at least one of my coworkers to appreciate this animal; now to convert the rest of the world.

(Of course you MUST watch them mate--it is so beautiful that it makes the awkward grunting efforts of vertebrates look absolutely absurd.)

Dusky slug, Arion subfuscus

The dusky slug is a common garden mollusk native to Europe now common across most of northeastern North America. This one is making short work of the oyster mushrooms on the stump in the front yard.

Much of the most beautiful and fascinating wildlife on Antigua is at the beach. This is a tiny mollusk with mother-of-pearl and a spot of copper blue.

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Photos by urbpan. Location: My front step, Brookline.

Urban species #319: Greenhouse slug Milax gagates

It is fortunate, for small urban invertebrates and those of us who appreciate them, that this has been an uncommonly warm fall in Boston. I was excited this morning, while waiting for my ride, to discover a new slug--well, one new to me. At first I thought it was my first glimpse of a terrestrial mollusk native to New England, but some research, including a look at a slug key, proved otherwise.

This particular shell-less snail is probably Milax gagates, or greenhouse slug. The greenhouse slug is originally native to southwestern Europe, but has been transported around the world, from greenhouse to garden. It now occurs on both coasts of North America, the southeast coast of Australia, and the islands of Britain, Bermuda, the Canary Islands, and Easter Island (map). Not shown on that map, but also part of the greenhouse slug's range, is the ever put-upon (ecologically speaking) nation of New Zealand. It seems likely that in its new ranges it lives near cultivated and landscaped plants only. Most of the available information about this species relates to limiting its potentially deleterious effect on agriculture.

Features distinguishing this slug from others include the keel along the tail, and its color pattern. This last feature is variable, with some individuals tending toward very dark coloring. Some sources list the species as the "black keeled slug," especially the Australian sources.


The keeled tail is visible here.

Photos by urbpan. Location, on a European beech tree, in the Riverway, Boston.

Urban species #230: Leopard Slug Limax maximus

It's no banana slug, but the leopard slug is an impressive animal nonetheless. Stretching out thin to nearly six inches long, it is easily the largest terrestrial mollusk found in eastern North America. It's bold patterns and large size make it a striking and beautiful creature even, one is hopeful, to those who generally dislike invertebrates. Leopard slugs are common in yards and gardens in the city, but rare even a short distance into the suburbs. This seems counterintuitive, but the leopard slug is an introduced species, familiar to Europeans as the spotted garden slug. Apparently it has adapted well to living alongside humans and their buildings, but for some reason can not thrive in the American countryside.

Leopard slugs feed at night, on a variety of different substances. They consume fungi, as well as decomposing and living plants. Gardeners who are bothered by slugs should be happy that the leopard slug preys on other slugs. They also will eat pet food left outside, and will feed on animal droppings and carrion. Their omnivorous habits have probably helped suit them to an urban existence. Besides Europe and North America, they are found throughout urban Australia and South Africa. Like European woodlice, they have been brought anywhere European soil has been brought.

They are hermaphrodites, and two individuals fertilize one another in a mating pendulum, entwirled about one another in a slimy embrace. Unfortunately this ritual occurs in the wee hours of the night, and few observers get the privilege of witnessing it.


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