The Song of the Ghost Crab

By Dr Patricia Groves

The topic of the lecture is "The Spiny Tailed Lizard in the Occasional Diet of Traditional Inland Omani Societies". One would expect this lecture to be given by a biologist, but no — we are gathered to hear the Chair of the Department of Archaeology at Sultan Qaboos University, Dr Ali Tigani el Mahi, lecture on lizards. So why is our eminent Archaeologist looking at lizards instead of digging up artifacts?

Archaeologists seek clues to help reconstruct life in extinct cultures. Hard material evidence, such as the remains of pottery and tools, can help us to understand basic components of a culture, but food evidence can yield valuable information closer to the core of life — information about the habits of people, their health, and even their migratory patterns.

The problem is of course that food evidence is not often found through traditional archaeological methods such as excavation. And so Dr El Mahi must find an inventive solution to cast light on the culture of Oman in earlier times. This he did by gaining the confidence of Bedouin elders in the Interior who remember the old ways.

The spiny tailed lizard was eaten, not as a part of the regular diet, which in traditional societies is connected to the seasons, but, occasionally, as a high protein supplement. This interesting lizard looks like a tiny dinosaur and lives in deep underground holes which would take the hunter hours to dig out. Instead the Bedouin trapped the spiny tailed lizard with clever snares of twisted rope, the shape of which appears in the ancient rock art of the region.

The unlucky lizard was eaten roasted; and, more significantly, often bartered. Tracing the fate of the lizard revealed the dietary interdependencies and cultural symbiosis of the coastal fishermen, the Interior Bedu and the Oasis farmers. Altogether a fascinating story told by Dr El Mahi in quite exciting mystery sequences as he solved the riddle of the spiny tailed lizard.

Now what should the tale of the lizard be followed by, but The Song of the Left-Handed Ghost Crab. It cannot be said that crab characters have entered the popular imagination, or even that many of us pay much attention when we see them scurrying about the beach. Yet, David Clayton, Professor of Biology at Sultan Qaboos University, has concentrated on the study of these creatures and speaks of them with passionate interest and great affection.

Crabs come in all sorts of species with long Latin names like Uca lactea annulipes and Lophozozymus cristatus. The species that has caught the attention of Dr Clayton particularly is Ocypode jousseaumei, more imaginatively called the "Ghost Crab", because it is very fast, dark and disappearing. Suddenly you see it and just as suddenly it is gone.

Hearing the ghost crab, though, is the ultimate experience. The male ghost crab "sings" by using its claws as drumming instruments against the surface of the sand and by playing on its large left-hand claw as if it were a scratchy violin. Like all great song, the crab's song is for love. He is calling out in the hope of attracting a lovely mate to his courtship burrow in the sand.

On the coast of Oman there are four kinds of ghost crab, some indigenous and some from India and Africa. They are beautifully marked, one in brilliant blue with yellow, and all have distinct telescopic eyes which give them an extra-terrestrial aura. In a skillful, high-tech presentation delivered with charm and humour, Dr Clayton animated the hidden behavioural ecology of the crab communities which dot the shores of the Sultanate.

We saw a painter's array of arresting colours in plain and spotted patterns as crabs of different species darted across the screen. Some were aggressively defending their territory from raiders and marauders and others were lying in wait on the porches of their burrows for passing beauties. By the end of the evening, there was not a person in the audience who had not become a true fan of a crab called Ocypode jousseaumei, or "Jos" for short.