Current sea ice conditions may be optimal for emperor penguin population, which is estimated to be seven times larger than during ice age.

Antarctic sea ice levels are perfect for emperor penguins, according to researchers, who have found the frozen continent has in the past been too cold for the bird.

A team of researchers, including scientists from the University of Tasmania and the Australian Antarctic Division, has been investigating how emperor penguin numbers have varied over centuries.

The lead researcher, Jane Younger, said that despite emperor penguins being accustomed to temperatures of -30C, the last ice age seems to have been a snap too cold for them, when their population was about seven times smaller than in 2015.

“Due to there being about twice as much sea ice compared to current conditions, the penguins were unable to breed in more than a few locations around Antarctic ,” Younger said.

“The distances from the open ocean, where the penguins feed, to the stable sea ice where they breed was probably too far.”

The finding suggests current sea ice conditions might be optimal for the emperor penguin population, but researchers have yet to determine the impact of further global warming.

A penguin species that lived millions of years ago would have dwarfed today’s biggest living penguins and stood as tall as most humans, according to analysis of fossils by a team of researchers from the La Plata Museum in Argentina.

Palaeeudyptes klekowskii has already been dubbed  the  , colossus penguin and is the most complete fossil ever uncovered from the Antarctic. The unearthed bones are 37m years old and include the longest recorded fused ankle-foot bone as well as parts of a wing bone.

From those bones, researchers estimated the species would have stood 2m tall from toe to beak tip, and weighed as much as 115kg. Standing normally, beak down, the penguin would have be around 1.6m tall, the team reported in the journal Geobios.

By comparison, the tallest and heaviest living species, the emperor penguin (Aptenodytes forsteri), stands 1.1m high and weighs just under 50kg.

Being of a larger build has its advantages, as bigger penguins could dive underwater to hunt fish for significantly longer periods of time compared to smaller species. A penguin the size of Palaeeudyptes klekowskii could stay underwater for up to 40 minutes.

Studying wild animals is crucial if we are to understand why they behave the way they do. But what if the apparently passive act of observation changes the way they behave? For decades, behavioural ecologists have been very mindful of this problem. A paper, just out in Natural Methods  suggests a cunning new way to collect data from wild animals without causing them undue stress.

There are many ways to study the behaviour of wild animals. You can go out and gain their trust, hoping they get so comfortable with your presence that they carry on as if you weren’t there at all. Or you might want to fit your study population with some kind of gizmo that can collect (and maybe even transmit) data in your absence. But even devices like these are likely to alter behaviour: increasing drag, for instance.

A microchip implanted beneath the skin (as is now routinely performed for pets) is much more likely to go unnoticed by the animal. The snag is that in order to scan the chip and identify the individual, you have to get pretty close. Researchers have now come up with an alternative: sending in a remote-controlled robot equipped with a scanning device, the ability to collect all sorts of data on the focal animal and then transmit it into the ether. Testing this method out on king penguins, they reveal that it is likely to be a whole lot less stressful for the animals.

When approached by a human, for instance, a penguin’s heart rate increased by an average of 35 beats per minute. When the rover came at it, its heart rate also increased, but only by around 24 beats per minute. In addition, a human caused the target penguin to move much more (average of 43 cm) than the rover (just 8cm). With the robot, the penguins were also much quicker to return to their original physiological state.

The researchers went on to see if emperor penguins had a similarly relaxed reaction to robots. Many were wary. But when the scientists dressed up the rover as a baby penguin, everyone was happy. “Chicks and adults were even heard vocalizing at the camouflaged rover, and it was able to infiltrate a crèche without disturbance,” note Yvon Le Maho and colleagues.This set-up is obviously not going to be workable in every setting. But it certainly does open up a lot of exciting possibilities for students of animal behaviour. Not to mention some rather wonderful photographic opportunities.