Today Cavannagh Cave is a small, rather unsighty cave in the limestone cliffs of Katouche Valley. This is the most likely place where in 1868 were discovered large bones – remains of an extinct rodent Amblyrhiza inundata, which was up to 200 kg heavy.

Giant rodents

In Pleistocene, when the sea level was considerably lower than now, Anguilla together with the nearby St. Martin and some other islands formed a single landmass.

It seems that hutias – nutria-like rodents of the Caribbean – had suitable life conditions on this island and were not endangered by predators. As a result, these animals became larger and larger with every generation until they were up to 2 m long and up to 200 kg heavy. Existing hutias today are some 2 kg heavy and 0.2 – 0.5 m long, while the world’s largest living rodents – capybaras – are some 50 kg heavy.

Giant hutias of Anguilla – blunt-toothed giant hutias (Amblyrhiza inundata) – were some of the largest rodents ever, but not the largest ones. Some 4 million years ago in South America lived Josephoartigasia monesi – this rodent was up to 1.3 tons heavy.

Flood and extinction

As the sea level raised at the end of Pleistocene, giant hutias had less and less land to sustain them. Ancient land divided into smaller islands which were too small to maintain large populations of these large animals. As the number of giant hutias fell below 1000 and less, the population was not viable anymore and species went extinct.

It is little likely that there were any live giant hutias when first people came to Anguilla sometimes around 1300 BC.

Phosphates and bones

Anguilla has rather many small caves which have formed in the early Miocene limestone. Bats and other animals have lived in these caves for millennia and their dung and carcasses of dead animals accumulated on the cave floor, forming a thick layer of phosphatic sediments.

These phosphates – valuable fertilizer – were mined in Caribbean caves in the 19th century. No one knows how many palaeontological (and possibly – archaeological) values have been lost in process.

Discovery of giant hutia

One such sample of phosphate sediments was sent from Anguilla to Philadelphia (United States) in 1868 to estimate the value of fertilizer. Fractions of bones were discovered in this sample and were given to American paleontologist Edward Drinker Cope. The find was very interesting – bones belonged to an unknown, enormous rodent.

Cope asked a physician from St. Martin, H. E. van Rijgersma to look for additional specimens in Anguilla. Rijgersma visited Anguilla several times and brought back fine samples of bones. Unfortunately, he did not identify where he found them, he just wrote that bones were found in Bat Cave. Such place name today is not applied to any cave on the island.

It is though known that bones of this extinct animal were found in Katouche Valley and Cavannagh Cave is the most likely place of the discovery.


  1. Donald A. McFarlane, Ross D. E. MacPhee. Amblyrhiza and the Quaternary Bone Caves of Anguilla, British West Indies, Cave Science Vol 16, Nr. 1., April 1989. Accessed on October 5, 2012
Cavannagh Cave on the map
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Location, GPS coordinates: 18.2115 N 63.0717 W (mistake up to 100 m)
Categories: Caves, Fossil finds
Values: Biology, Geology
Rating: 2 out of 10 stars
Where is located? North America, Caribbean, Anguilla, near the north-western coast, between The Valley and North Hill, in the southern side of Katouche Valley, north from the Governor’s Residence
Alternate names: Cavannaugh Cave
Length: 87 m
Fossil finds: Blunt-toothed giant hutia (Amblyrhiza inundata)

Landmarks of Anguilla

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Beach in Anguilla / Christine Warner Hawks, Flickr / CC BY 2.0
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Entrance into Puerto Princesa Subterranean River / , Flickr / CC BY 2.0
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