Giant bats used to soar above Otago

The bats lived between 19 and 16 million years ago.
The bats lived between 19 and 16 million years ago. Photo credit: Supplied

New Zealand used to be home to massive bats three times bigger than any you'd find today.

Teeth and bones found near the former gold mining town of St Bathans in Otago were discovered by a team of scientists from New Zealand, Australia, the UK and US.

The bats lived between 19 and 16 million years ago, and have been named Vulcanops jennyworthyae.

Vulcanops honours the Roman god of fire and the town's historic Vulcan Hotel, while the second half refers to team member Jenny Worthy, who found the fossils.

They lived in and around a prehistoric lake that once covered much of the present Maniototo region of the South Island. At the time, temperatures were up to 12degC higher than today - meaning the South Island was semi-tropical, and the region was covered in ferns and forests.

Its size - 40g - might not sound big, but it's a lot bigger than New Zealand's existing bat species, which are about the size of a thumb and weigh about 10g.

"New Zealand's burrowing bats are also renowned for their extremely broad diet," says study first author Professor Sue Hand of the University of New South Wales.

"They eat insects and other invertebrates such as weta and spiders, which they catch on the wing or chase by foot. And they also regularly consume fruit, flowers and nectar.

"However, Vulcanops' specialised teeth and large size suggest it had a different diet, capable of eating even more plant food as well as small vertebrates - a diet more like some of its South American cousins. We don't see this in Australasian bats today."

Vulcanops went extinct after the early Miocene period - as did a number of species in the region, including crocodiles, turtles, pigeons, parrots and palaelodids, which were a bit like flamingos. None were able to adapt to the cooling climate, which eventually resulted in the Pleistocene's ice ages.

Today, New Zealand has only two bat species - the only native land mammals, the rest having been brought here in the past 800 years.

"These bats, along with land turtles and crocodiles, show that major groups of animals have been lost from New Zealand," said study co-author Professor Paul Scofield of Canterbury Museum.

"They show that the iconic survivors of this lost fauna - the tuatara, moa, kiwi, acanthisittid wrens, and leiopelmatid frogs - evolved in a far more complex community that hitherto thought."

The research was published in journal Scientific Reports.