When it comes to a beauty contest, the African manatee, a bloated sea cow that grazes the coastal waters off west Africa, will never win any prizes. But should an unprepossessing mugshot condemn a species to extinction?

According to a new study, rampant bias exists among researchers towards "cuter and more interesting" animals. The meerkat has clocked up more than 100 published studies since 1994. The manatee has been the subject of just 14, and academic neglect may be a vital factor in its currently parlous position. "Scientists are people too," says Morgan Trimble, a conservation scientist at the University of Pretoria in South Africa, who carried out the study. "And many of them want to work with the big and furry stuff."

For years, conservationists have wrestled with the problem that high-profile species draw the most attention, and therefore the most money. It is no accident that conservation group WWF is known by its distinctive panda logo.

Supporters of this approach argue that "charismatic mega-fauna" attract much-needed funds for other species too. Sally Wren of the Zoological Society of London argues: "Charismatic species can be used as flagships to help protect areas and reduce threats, the effect of which often also benefits the less compelling species in the same region."

Critics, including the founders of a website called Endangered Ugly Things, point out that some less glamorous creatures fall through the conservation net as a result. "There has been a long-standing debate about the conservation of charismatic species such as gorillas and elephants over others. We wanted to see if this was a deeper problem and if it applied to scientific research and funding," says Trimble. "The bottom line is that there is not enough money to go around and what we choose to learn about could influence what we conserve."

With her University of Pretoria colleague Rudi van Aarde, Trimble surveyed scientific papers published from 1994 to 2008, looking for mentions of almost 2,000 species found across southern Africa. They combined this information with a global list produced by the International Union for Conservation of Nature, which classifies each animal according to its endangered status.

Writing in the latest issue of the journal Conservation Biology, the scientists say their study shows that: "In the eyes of science, all species are not created equal." They add: "A few species commanded a great proportion of scientific attention, whereas for many species, information that might inform conservation is virtually non-existent."

Threatened large mammals dominated the studies, appearing in 500 times as many published papers as threatened amphibians. Threatened reptiles, birds and small mammals also received much less attention. The most studied animals were chimpanzees, with 1,855 mentions, and leopards, with 1,241 mentions. Even within the relatively well-studied group of threatened large animals, more than two-thirds of scientific effort went on less than a third of species. For threatened reptiles, some 98% of research studied less than a quarter of species.

The scientists, who call such disparities "disconcerting", say: "It is unlikely that these figures represent the relative importance of these animal groups from the perspective of ecosystem conservation... it is time for a proper evaluation of scientific investments."

Trimble said research on animals was skewed for more reasons than the appeal of charismatic species. Meerkats live in complex social groups and chimps are our closest relative. Commercial factors can also play a role. Some of the most studied small mammals draw attention because they are pets, while the three most studied amphibians are also kept as pets. Scientists may also be interested in animals that occur near to them, which may explain why the new study showed that lower-risk species of amphibians and small mammals received more attention than threatened species.

The study suggests skewed research has led conservationists to overlook the extinction of ignored species. Wren says this may be exaggerated. "But it has had a large impact on our response to diversity loss. The less well-known species, which might have been easy conservation wins, have often been neglected as efforts are directed elsewhere."

Colin Butfield, head of campaigns at WWF-UK, said: "There is no point in saving one species when we are losing whole habitats. We would like to see more research looking at the health of entire ecosystems to determine the underlying cause of species' extinction."