Amphibian Week Day 5

May 7, 2021 • 9:02 pm

by Greg Mayer

For the end of Amphibian Week, we have a photo gallery, starting with my late, lamented, Toady, who was collected by David Wingate, Bermuda’s foremost naturalist, in 1999, and who died in 2019, at the age of 20+ years. The Giant Toad, Bufo marinus, (also known as the Marine Toad or Cane Toad) is native to the continental American tropics and subtropics, and was introduced to Bermuda.

Giant Toad, Bufo marinus, Bermuda (collected in 1999; photo taken in 2012).

Note the enormous parotoid gland behind the eye, which secretes poisons that can protect the toad from predators.

Giant Toad, Bufo marinus, Bermuda (collected in 1999; photo taken in 2012).

Next, from Chis Petersen of DoD PARC, a gallery of amphibians that are found on U.S, military bases, and this report summarizing the status of threatened and endangered species on these bases (it includes both amphibians and reptiles).

My thanks to Chris, who has been distributing amphibian images, documents, and links throughout Amphibian Week. (If you’re wondering why the Department of Defense is involved in conservation, we’ve dealt with that before at WEIT. The short answer is that 1) the military must obey applicable environmental and conservation laws on military lands, and 2) certain animals pose practical issues for the military (e.g., venomous snakes). The Navy, which I know best, employs a number of professional herpetologists. Recall as well that the military has often enabled scientific exploration (the Beagle, for example, was a Royal Navy ship), and military reservations have sometimes had the best preserved habitats (e.g., much of the Patuxent National Wildlife Refuge was annexed from Fort Meade.)

Department of Defense Partners in Amphibian and Reptile Conservation. 2019. Department of Defense Herpetofauna Conservation Status Summary. Department of Defense Legacy Resource Management Program. pdf

Reader’s wildlife photos

November 6, 2019 • 11:30 am

by Greg Mayer

A corespondent from Florida sends the following photos from Fort Myers. First up, a giant or marine or cane toad (Bufo marinus) that is living under a beehive. In this first photo, you can see that the variegated coloring is fairly cryptic against the leaf litter background.

Bufo marinus, Fort Myers, Florida, 3 November 2019.

Getting a little closer, a few things are notable. First, from the body shape (which I am tempted to describe as “jowly”, despite the fact that it’s her abdomen that’s distended), I can tell this is a fairly large individual. My correspondent, unprompted, stated it was about 15 cm long, which sounds about right for a big one. The biggest ones are in the Guianas, where they get to about 25 cm.

Bufo marinus, Fort Myers, Florida, 3 November 2019.

Second, as the preceding sentence implies, she is a female. Females are larger, and retain the brown/black/tan blotching and spotting of the juveniles. This coloration is typical of many species of toads at all ages, and in both sexes. Adult males of marinus are distinctive in becoming uni-colored in some olive drab-like shade (see a male here). And finally, note the large parotoid gland extending from above the arm towards the eye. This gland can secrete a milky toxin, which is part of the toad’s defenses.

These toads, native from the lower Rio Grande down into South America, have been introduced into Florida, and to many other places, including islands in the West Indies and the Pacific, and Australia, where they picked up the moniker “cane toad”, which is rapidly becoming the vernacular name throughout the English-speaking world. I always called them “marine toads”, from their scientific name. They are not marine (although they can be found in brackish situations), and it’s just a coincidence that U.S. Marines have landed in so many of the places that the toads were introduced (e.g. Hispaniola, Puerto Rico, New Guinea, the Philippines, etc.).

Next up a brown anole (Anolis sagrei). This species and its close relatives are widespread in the West Indies, including Cuba and the Bahamas, and have, like the toad, been introduced in to Florida and many other places. The green anole, Anolis carolinensis, native to Florida, is now perhaps less abundant than prior to the arrival of sagrei, but the native is not threatened by the invader. In Cuba, the two species (or close relatives) live side by side, with the green anole higher in the vegetation, the brown anole lower, and this ecological situation has now been replicated in Florida; the two species were “preadapted” for coexistence by their long joint history in Cuba.

Anolis sagrei, Fort Myers, Florida, 31 October 2019.

Last but not least, something higher on the scala naturae, an anhinga, Anhinga anhinga, drying its feathers. These diving birds, which stab their piscine prey with their bills, do not have waterproof feathers.

Anhinga anhinga, Fort Myers, Florida, 31 October 2019.

The marine toad

September 3, 2015 • 9:00 am

by Greg Mayer

Jerry had us spot the toad a few posts ago (I earlier posted an easier ‘spot the frog‘), and in the comments some readers mentioned the marine toad, Bufo (Rhinella) marinus, also known as the cane toad (especially in Australia) or the giant toad. This species, native from south Texas to central Brazil, has been widely introduced in the West Indies (including Bermuda), Florida, Australia, and the Pacific islands. They were introduced primarily as a way to control a beetle which attacked sugar cane; the toads were not very good at this, and have had negative effects on more desirable faunal elements in some places.

Adult female Bufo (Rhinella) marinus, in 2012; origianlly collected on Bermuda, 1999.
Adult female Bufo (Rhinella) marinus, in 2012 in my back yard (Racine, Wisconsin); originally collected on Bermuda, 1999.

The above is my pet female, collected for me during a visit to Bermuda in 1999 by Bermuda’s foremost naturalist and conservationist, David Wingate. He has succeeded in eliminating the toads from Nonsuch Island, a preserve where the restoration of Bermuda’s indigenous fauna and flora is being promoted, with considerable success. She is fairly large, being 165 mm snout-vent length; unfortunately, I did not measure her when I first got her, but she was adult-sized at the time. The largest one I have ever found myself was a 178 mm one in Nicaragua. They get up to around 250 mm; the largest ones are said to be from the Guianas. A rather large preserved individual at the Museum of Comparative Zoology is about 230 mm long, and has long resided in a large Agassiz jar on the coffee table in the herpetology department.

In addition to being large, she’s getting old. I had thought she must be a record, but found that ages up to 25 years have been reported. “Toady” must be at least 17, perhaps a bit more, so she’s got a few years to go. Her only sign of aging is a cataract-like opacity in her right eye, which does not seem to have interfered with her ability to spot prey.

Notice the very large parotoid gland behind her ear; these secrete a milky poison when the toad is stressed, and I have been told that d*gs, not being terribly bright, have been sickened and even killed by attempting to ingest the toads. In South America, carnivorous mammals are said to flip the toads over, and eat them from the belly side, where the skin does not contain toxins (or at least not as much). When being defensive, Toady angles her back toward the unwanted stimulus. The best overall guide to the biology of these toads is still “The Marine Toad, Bufo marinus: a natural history resume of native populations” by my friend and mentor, George Zug, and his wife Pat.

Easteal, S. 1981. The history of introductions of Bufo marinus (Amphibia: Anura); a natural experiment in evolution. Biological Journal of the Linnean Society 16:93-113. abstract

Slade, R.W. and C. Moritz. 1988. Phylogeography of Bufo marinus from its natural and introduced ranges. Proceedings of the Royal Society of London B 265:769-777.  pdf

Wingate, D.B. 2011. The successful elimination of Cane toads, Bufo marinus, from an island with breeding habitat off Bermuda. Biological Invasions 13:1487-1492.  abstract

Zug, G.R. and P. B. Zug. 1979. The marine toad, Bufo marinus: a natural history resume of native populations. Smithsonian Contributions to Zoology 284, 58 pp.   pdf