Tracking Down The Undersea Elephant
The Age
Monday May 17, 1999
There was something odd about the structures on view through the microscope. About 47 long thin canals were neatly arranged along the foetal elephant's kidney. They weren't illustrated in modern textbooks on mammalian embryology; they weren't even mentioned.
Yet they appeared in all five elephant foetuses being examined by Ms Ann Gaeth, who was then a zoology honors student at Melbourne University.
What these structures would come to show, she would later argue, was that elephants once lived underwater.
``We thought `This is pretty exciting, they have all these foetal features that point to an aquatic ancestry'," she said. ``That's when we went `Wow, we want to publish'."
Ms Gaeth spent months preparing a scientific paper with the help of Professor Roger Short and the head of Melbourne's zoology department, Professor Marilyn Renfree. The paper was submitted to two of the world's most prestigious scientific journals, Science and Nature.
``We thought it was pretty hot stuff and we thought they would jump on it," Ms Gaeth said. Both journals rejected the paper.
The researchers then sent the paper to be published in the Proceedings of the US National Academy of Science. It was accepted and published in the highly regarded journal on Tuesday.
The reaction has been phenomenal. Ms Gaeth has been interviewed about her research by the BBC in England and Scotland, the ABC, the American Broadcasting Corporation, New Scientist, the Discovery Channel and The Economist.
But on Monday an unexpected call came through. It was Science. Could they have an interview?
The high profile is fine, but for Ms Gaeth the aim remains the same: to give people, through her research, a better understanding of elephants.
Caring for animals has always been a focus for Ms Gaeth. She wanted to be a vet for years. After completing first-year science (a prerequisite for veterinary science) she found she enjoyed zoology and wanted to stay in research.
In two months Ms Gaeth will have finished her PhD. Her work on elephants has inspired her to become involved in conservation biology.
``Because I've worked on endangered species I want to move into that area further, whether it's the control of pest species or even native animals that have become pests."
Until 1993 no one had studied the early embryology of elephants. That changed when five elephant foetuses became available to Professor Short at Melbourne University early in 1993. The foetuses were taken from African elephants culled in Kruger National Park, South Africa.
Ms Gaeth began her honors year investigating how testes develop in elephants. She had sectioned the five elephant foetuses so she could look at how the gonads differentiate into testes.
The elephant sections, about 10 micrometres thick, were stained to show up the structures and placed on glass slides. With hundreds of sections before her, Ms Gaeth began the cumbersome task of identifying the embryonic structures.
After much searching Ms Gaeth found an old textbook with a hand-drawn diagram. The picture was similar to the image on the slide. But the drawing was of a structure found in fish, not elephants. The picture showed a nephrostome - a funnel-shaped canal that drains the peritoneal cavity of the abdomen. The textbook described nephrostomes as rudimentary and not usually seen in mammals.
She then began researching which other animals had nephrostomes. The search took months but revealed that nephrostomes are found in such water-dwelling animals as fish, frogs and platypuses.
In fish and frogs the nephrostomes are used to regulate the flow of water in and out of their bodies. Their presence in foetal elephants was the first sign that these modern day land-dwellers once lived in water.
``We didn't really realise the enormity of it until we linked it to all the other features of foetal development," Ms Gaeth said.
© 1999 The Age