by Marisa Giorgi, Discovery Centre Information Officer

When cabinets of curiosity were fashionable, this strange looking smooth ball would be a worthy addition. In those early 16^th century permutations of what would become museums, what could be more appropriate than a crocodile bezoar or hairball nestled among a collection of peculiar oddities on display?

Hair, along with hooves, claws, and fingernails for that matter, is made of a substance called keratin. It is not easy to break down when swallowed. Crocodiles have powerful digestive systems to deal with the food they eat, which is mostly whole animals. Most parts of their prey, including bones, are easily digested, but no so the keratin.

When crocodiles eat animals with hair or fur, such wild pig and wallabies, some of this material passes through the digestive tract and is expelled with faeces. But some remains in the gut and can cause irritation.

The accumulated hair may form a ball, sometimes smooth like this one, which is later regurgitated. This is called a bezoar, defined as a solid mass of indigestible material that accumulates in the digestive tract of an animal, sometimes causing a blockage.

Other animals also create bezoars in their digestive tracts, and we are all too familiar with cat hairballs! Even goats can have them. Goat bezoars were prized in medieval medicine for warding off the risk of being poisoned. Gascoign’s powder, a 17^th century concoction composed predominantly of crab’s claw, was reputed to contain Oriental Bezoars obtained from the fourth stomach of the Persian bezoar goat. This powder claimed to be a cure-all, treating everything from epilepsy and melancholy to jaundice and worms. Bezoars were also collected as charms encased in gold as far back as 1200 B.C. in India. A bezoar was even recorded as part of the inventory among the possessions of Queen Elizabeth the First.

A mammal hairball is formed around a nucleus to which hairs licked off the body then attach creating a hairball. Humans with trichophagia, a compulsion to eat hair (also called the Rapunzel syndrome) can also develop bezoars that are sometimes called trichobezoars.

An unusual form of human bezoar has occurred among a small number of French polishers, who were known to occasionally drink their alcohol rich polish which resulted in some cases where a cast of the stomach was produced from deposits of shellac.

One of the most prized bezoars is ambergris. This is used in the production of perfume and fetches prices of up to $40,000 US a kilogram. It develops in a Sperm Whale’s stomach and is formed to isolate the sharp indigestible squid beaks the whale has eaten by sealing them in a waxy coating. There is some debate as to whether ambergris is regurgitated or fully passes through the whale’s digestive tract. Either way, whale bezoar was claimed to cure impotence in 10^th century Turkey and 800 years later it was used as an aphrodisiac by Casanova.

Bezoars are sometimes mistakenly confused with gastroliths. They are the stones that are swallowed by some animals including crocodiles and alligators, some birds and even some ancient marine reptiles, to help break up and digest food.

One could liken the crocodile bezoar to that beautiful prized jewel, the pearl, which is formed by the same principle of neutralising a foreign body (such as a grain of sand) within the animal. Well, let us all admire the crocodilian pearl, the bezoar.

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