Some people don’t like sharing their food – we all have a friend who gets cranky when you steal a chip from their plate. For wild animals, this makes sense, because any food shared is energy lost that could otherwise have been used to pursue more food.
So it was a big surprise to discover wild leopard seals feeding alongside one another while eating king penguins at South Georgia, a remote island in the southern Atlantic Ocean. On top of this, they may have even been cooperating with each other to eat these enormous seabirds.
We report this fascinating observation in a new study published today in the journal Polar Biology.
Can’t we just all get along?
Leopard seals have a ferocious reputation as one of the top predators in the Antarctic ecosystem. They are infamously the “principal enemy of the penguin”, as immortalised in the film Happy Feet.
But when they eat penguins, leopard seals are normally highly territorial, scaring off rivals by lunging at them with a fearsome set of teeth. Animal-mounted cameras have even revealed that leopard seals ambush each other to steal captured prey.
But that’s not what was seen when the film crew working on the Netflix documentary series Our Planet visited South Georgia. Instead, they were astonished to find wild leopard seals floating alongside one another dining together on a king penguin carcass, taking it in turns to tear off pieces of food.
Too costly to fight
Given how aggressive leopard seals normally are around food, why were these seals behaving so out of character?
Consider this: if you were at an all-you-can-eat buffet and a stranger sat at your table and began eating your food, would you chase them away or let them share with you, knowing you could easily get more afterwards?
When food is very abundant, it may well be cheaper to share than to fight. Penguin colonies offer a near-constant supply of potential prey, attracting scores of predators. In this case, up to 36 leopard seals were seen near the colony at the same time.
So if a seal paused feeding to scare or fight off a rival, there is a good chance a third seal would sneak in and steal the food. In this situation it makes more sense to focus on eating as much as possible, as fast as possible – tolerating some food theft if necessary so as to avoid wasting energy on fighting that would risk losing the prey altogether.
The seals didn’t get along perfectly all the time. We saw some aggression, but perhaps this is to be expected if they are just tolerating each other out of necessity.
Do leopard seals cooperate to eat large prey?
Another explanation for these unexpected observations is that leopard seals might be cooperating to make it easier to consume such large prey.
Unlike northern seals, leopard seals don’t have clawed paws to help them hold prey. Instead, they have paddle-like flippers with tiny claws, forcing them to vigorously thrash the prey from side to side in their teeth to tear it into pieces small enough to swallow. This energy-intensive eating style is even harder when the prey is large – like adult king penguins.
Alternatively, if two animals hold the prey between them, one can act as an anchor while the other tears off a chunk of meat. This saves a lot of energy that would otherwise be wasted shaking the prey around.
This type of cooperative food processing is actually quite common among aquatic top predators, such as killer whales and crocodiles, that can’t easily hold onto food.
The unusual case of the sharing seal
This last possibility made us rethink the interpretation of a famous encounter between a wild leopard seal and National Geographic photographer Paul Nicklen. On entering the water, Nicklen was repeatedly approached by a seal that appeared to be trying to feed him a penguin in an act of unexpected altruism. But perhaps this was not a free gift, but an offer to cooperate.
The latest discovery is a great example of how new technology can help researchers make close-hand observations of wild animals. By using a camera drone, the film-makers could fly above the animals without disturbing them, allowing them to observe behaviours that have so far gone unnoticed.
The remoteness of Antarctic ecosystems can make it hard to connect with the wildlife there, but these advances in technology are helping to provide new windows into this icy world.
Romane H. Cristescu, University of the Sunshine Coast; Anthony Schultz, University of the Sunshine Coast; Celine Frere, University of the Sunshine Coast; David Schoeman, University of the Sunshine Coast, and Kylie Scales, University of the Sunshine Coast
In a country like Australia – a wealthy, economically and politically stable nation with multiple environmental laws and comparatively effective governance – the public could be forgiven for assuming that environmental laws are effective in protecting threatened species.
But our new research, published recently in Animal Conservation, used koala-detecting dogs to find vulnerable koalas in places developers assumed they wouldn’t live. This highlights the flaws of environmental protections that prioritise efficiency over accuracy.
Environmental impact assessments
Every new infrastructure project must carry out an Environmental Impact Assessment (EIA) to see whether it will affect a threatened species. If this is the case, the logical next step is to try to avoid this by redesigning the project.
But this rarely happens in reality, as we saw recently for the endangered black-throated finch.
More often, when the EIA suggests an unavoidable impact the response is to identify mitigation and compensation measures, often in the form of “offsets”. These are swathes of comparable habitat assumed to “compensate” the impacted species for the habitat lost to the development.
To take koalas as an example, developers building houses might be required to buy and secure land to compensate for lost habitat. Or a new road might need fencing and underpasses to allow koalas safe passage across (or under) roads.
These steps are defined in environmental regulations, and depend on the results from the original EIA.
An issue of assumptions
With koala numbers still declining, we investigated whether current survey guidelines for EIA were indeed adequate.
For an EIA to be effective, it is fundamental the environmental impact of a future development can be accurately anticipated and therefore appropriately managed. This relies, as a first step, on quantifying how the project will affect threatened species through ecological surveys of presence and extent of threatened species within the project’s footprint.
There are government guidelines to prescribe how these ecological surveys are performed. Every project has time and budget constraints, and therefore survey guidelines seek efficiency in accurately determining species’ presence.
As such, the Australian guidelines recommend focusing survey effort where there is the highest chance of finding a species of concern for the project. This sounded very logical – until we started testing the underlying assumptions.
We used a very accurate survey method – detection dogs – to locate koala droppings, and therefore identify koala habitat, in the entire footprint of proposed projects across Queensland. We did not target our efforts in areas we expected to be successful – therefore leaving out the bias of other surveys.
We found koalas did not always behave as one would expect. Targeting effort to certain areas, the “likely” koala habitat, to try increase efficiency risked missing koala hotspots.
In particular, the landscape koalas use is intensely modified by human activity. Koalas, like us, love living on the coast and in rich alluvial plains. That means we unexpectedly found them right in the middle of urban areas, along roads that – because they have the final remaining trees in dense agricultural landscapes – are now (counterintuitively) acting as corridors.
Assumptions about where koalas live can massively underestimate the impact of new infrastructure. In one case study, the habitat defined by recommended survey methods was about 50 times smaller than the size of the habitat actually affected.
If surveys miss or underestimate koala habitat while attempting to measure development impact, then we cannot expect to adequately avoid, mitigate or compensate the damage. If the first step fails, the rest of the process is fatally compromised. And this is bad news for koalas, among many other threatened species.
All parts of the landscape are important
What is needed is a paradigm shift. In a world where humans have affected every ecosystem on Earth, we cannot focus on protecting only pristine, high-quality areas for our threatened species. We can no longer afford to rely on assumptions.
This might seem like a big, and therefore expensive, ask. Yet ecosystems are a common resource owned by all of us, and those who seek to exploit these commons should bear the cost of demonstrating they understand (and therefore can mitigate) their impact.
The alternative is to risk society having to shoulder the environmental debt, as we have seen with abandoned mines.
The burden of proof should squarely reside with the proponent of a project to study thoroughly the project impact.
This is where the issue lies – proponents of projects are under time and budget constraints that push them to look for efficiencies. In this tug of war, the main losers tend to be the threatened species. We argue that this cannot continue, because for many threatened species, there is no longer much room for mistakes.
The environmental regulations that define survey requirements need to prioritise accuracy over efficiency.
A review of Australian’s primary environmental law, the Environment Protection and Biodiversity Conservation Act is due to begin by October this year. We call on the government to use this opportunity to ensure threatened species are truly protected during development.
The authors would like to gratefully acknowledge the contribution of Dr David Dique and Russell L. Miller to this research and the two original papers this piece is based upon (feature paper and response).
Romane H. Cristescu, Posdoc in Ecology, University of the Sunshine Coast; Anthony Schultz, PhD Candidate, University of the Sunshine Coast; Celine Frere, Senior lecturer, University of the Sunshine Coast; David Schoeman, Professor of Global-Change Ecology, University of the Sunshine Coast, and Kylie Scales, Senior lecturer, University of the Sunshine Coast
Animal populations have declined on average by 60% since 1970, and it’s predicted that around a million species are at risk of extinction. As more of the Earth’s biodiversity disappears and the human population grows, protected landscapes that are set aside to conserve biodiversity are increasingly important. Sadly, many are underfunded – some of Africa’s most treasured wildlife reserves operate in funding deficits of hundreds of millions of dollars.
In unfenced wilderness, scientists rarely have an inventory on the exact numbers of species in an area at a particular time. Instead they make inferences using one of many different survey approaches, including camera traps, track surveys, and drones. These methods can estimate how much and what kind of wildlife is present, but often require large amounts of effort, time and money.
Camera traps are placed in remote locations and activated by movement. They can collect vast quantities of data by taking photographs and videos of passing animals. But this can cost tens of thousands of dollars to run and once in the wild, cameras are at the mercy of curious wildlife.
Track surveys rely on specialist trackers, who aren’t always available and drones, while promising, have restricted access to many tourism areas in Africa. All of this makes wildlife monitoring difficult to carry out and repeat over large areas. Without knowing what’s out there, making conservation decisions based on evidence becomes almost impossible.
Citizen science on Safari
Tourism is one of the fastest growing industries in the world – 42m people visited sub-Saharan Africa in 2018 alone. Many come for the unique wildlife and unknowingly collect valuable conservation data with their phones and cameras. Photographs on social media are already being used to help track the illegal wildlife trade and how often areas of wilderness are visited by tourists.
Despite this, tourists and their guides are still an overlooked source of information. Could your holidays snaps help monitor endangered wildlife? In a recent study, we tested exactly this.
Partnering with a tour operator in Botswana, we approached all guests passing through a safari lodge over three months in the Okavango Delta and asked them if they were interested in contributing their photographs to help with conservation. We provided those interested with a small GPS logger – the type commonly used for tracking pet cats – so that we could see where the images were being taken.
We then collected, processed, and passed the images through computer models to estimate the densities of five large African carnivore species – lions, spotted hyaenas, leopards, African wild dogs and cheetahs. We compared these densities to those from three of the most popular carnivore survey approaches in Africa – camera trapping, track surveys, and call-in stations, which play sounds through a loudspeaker to attract wildlife so they can be counted.
The tourist photographs provided similar estimates to the other approaches and were, in total, cheaper to collect and process. Relying on tourists to help survey wildlife saved up to US$840 per survey season. Even better, it was the only method to detect cheetahs in the area – though so few were sighted that their total density couldn’t be confirmed.
Thousands of wildlife photographs are taken every day, and the study showed that we can use statistical models to cut through the noise and get valuable data for conservation. Still, relying on researchers to visit tourist groups and coordinate their photograph collection would be difficult to replicate across many areas. Luckily, that’s where wildlife tour operators could come in.
Tour operators could help collect tourist images to share with researchers. If the efforts of tourists were paired with AI that could process millions of images quickly, conservationists could have a simple and low-cost method for monitoring wildlife.
Tourist photographs are best suited for monitoring large species that live in areas often visited by tourists – species that tend to have high economic and ecological value. While this method perhaps isn’t as well suited to smaller species, it can still indirectly support their conservation by helping protect the landscapes they live in.
The line between true wilderness and landscapes modified by humans is becoming increasingly blurred, and more people are visiting wildlife in their natural habitats. This isn’t always a good thing, but maybe conservationists can use these travels to their advantage and help conserve some of the most iconic species on our planet.
Indian tiger numbers are up, according to one of the most detailed wildlife surveys ever conducted. Tiger populations have risen by 6%, to roughly 3,000 animals.
The massive survey may set a new world standard in counting large carnivores. The encouraging results validate India’s impressive investments in tiger conservation.
A mammoth effort
Large, solitary predators hate being seen. They owe their entire existence to being able to avoid detection by prey and sneak close before attacking.
Hence, when we want to count tigers, the tigers don’t help. But accurate population numbers are fundamental to good conservation. Every four years since 2006, the Indian government conducts a national census of tigers and other wildlife.
The efforts the project team undertakes to derive the tiger population estimate are nothing short of phenomenal: 44,000 field staff conducted almost 318,000 habitat surveys across 20 tiger-occupied states of India. Some 381,400 km² was checked for tigers and their prey.
(There is an application in with the Guinness Book of World Records to see if this is the largest wildlife survey ever conducted anywhere in the world.)
The team placed paired camera traps at 26,760 locations across 139 study sites and these collected almost 35 million photos (including 76,523 tiger and 51,337 leopard photos). These camera traps covered 86% of the entire tiger distribution in India. Where it was too dangerous to work in the field (14% of the tigers’ distribution) because of political conflict, robust models estimated population numbers.
Count the tigers
Collecting this volume of data would be an utter waste of time if it were poorly analysed. The teams took advice from some of the world’s foremost experts to sort the photos: pattern matching experts who could identify whether a photo of a tiger taken in the monsoon matched that of a tiger taken in the dry season while walking at a different angle, machine learning experts to speed up species identification, and spatial analysis experts to estimate the populations of tigers and their prey.
The research team took this advice and coupled it with their own knowledge of tiger ecology to develop a census that is unique among large carnivore studies.
We were fortunate enough to be among the non-Indian scientists invited to review this process. Peer review is a crucial part of any scientific endeavour, and especially important as early Indian tiger surveys were notoriously unreliable.
So how did they do? A total of 2,461 individual tigers older than one year of age were photo-captured. The overall tiger population in India was estimated at 2,967 individuals (with an error range of roughly 12%).
Out of this, 83.4% were estimated from camera-trap photos, and the rest estimated from robust modelling. Tiger numbers have increased by 6% per year, continuing the rate of increase from the 2014 census. This is a wonderful success for Indian conservation efforts.
However not all is rosy. There has been a 20% decline in areas occupied by tigers in 2014 to today, although tigers have moved into some new areas (some 8% of their Indian range is new). The coordinators of the tiger survey – Yadvendradev Jhala and Qamar Qureshi – conclude that while established and secure tiger populations in some parts of India have increased, small, isolated populations and those along corridors between established populations have gone extinct.
This highlights the need for conservation efforts to focus on improving connectivity between isolated populations, while incentivising the relocation of people out of core tiger areas, reducing poaching and improving habitat to increase prey resources.
This will be no easy task with India’s burgeoning population, but investment from private sector tourist corporations in land acquisition along corridors and the creation of community conservancies could supplement government funding for expanding protected corridors.
Curious Kids: why do tigers have whiskers?
The success of India’s census has led the governments of Nepal and Bangladesh to employ the same project team to help estimate their own tiger populations. These methods can – and should – be employed for other iconic, charismatic species that can be individually identified, such as jaguars in South and Central America; leopards, cheetahs, and hyenas in Africa, and possibly even quolls in Australia.
This article was co-authored by Chris Carbone, Senior Research Fellow at the Zoological Society of London.