Over the years, a lot of misinformation has been written about British Big Cats (Alien Big Cats). Much has been written by people who simply don't know what they are talking about, or who are passing on hearsay or garbled information. More worrying, some has been written by people who really ought to know better, but whose judgement is clouded by their belief in conspiracy theories. Some people desperately want to believe in big cats and will ignore any evidence to the contrary. Problems occur when the misinformation and zealotry ends up in news reports which are read by gullible people and the misinformation becomes a meme. In order to be taken seriously rather than dismissed as credulous cranks, big cat watchers need to get their facts and terminology correct and inject a healthy dose of scepticism.

Here are some straight facts stripped of hype. Compared to the sensational pro-British big cat reports, the straight facts and dose of genetics may seem rather boring. Humankind far prefers the exciting, if inaccurate, explanation over an explanation rooted in factual content.

Very probably. I am not going to deny that non-native felids are loose in Britain. They have been kept as exotic pets and in menageries for centuries and there has been ample opportunity for big cats to escape wither accidentally (enclosure damaged by storms etc) or deliberately (released into the wild by the owner). Recent escapes and recaptures are documented as are the captures of a Puma and a European Lynx, both of unknown provenance. Jungle Cats (F chaus, a small non-native species) have been found dead on the roadside. However, no big cats have been found dead by the roadside and no recent skeletal remains have been found in open areas, so their numbers in the wild would be very low.

There are probably also exotic cats kept illegally, perhaps inside houses or on private land where they attract no attention. When one of these illegally held exotics escapes, the owner cannot simply report it. The legislation on keeping and housing big cats was more lenient in parts of Ireland and there is the possibility that exotic cats have been obtained from there and brought to England on private boats without going through a major port. The most commonly kept pet big cats were leopard and melanistic leopard (black panther) although puma (American panther) and lions were also kept. Jaguars were far too intractable for a private owner. Correspondingly. sightings are predominantly black panthers (i.e. leopards since the puma does not have a melanistic form), pumas or lionesses (tawny) and leopards (sometimes reported as jaguars). Lynxes are also reported. But no tigers or maned male lions?

There is plenty of wildlife (deer, ponies, hares, rabbits, foxes), free-ranging livestock (sheep, calves, goats, poultry) and pets (dogs, cats) to support non-native felids, especially in rural areas. In India, the adaptable leopard can also be found in the town suburbs where it hunts domestic dogs and cats and may attack humans. Not every mysterious shape is a big cat, however much enthusiasts want it to be one.

Here is an example of a report of a non-native wild cat that escaped from a ship in Liverpool. It appears to have been one of the smaller cats, possibly a Geoffroy's cat, margay or ocelot: WILD CAT AT LARGE ESCAPE FROM CAGE ON SHIP, Derby Daily Telegraph, 29th June 1929: “A wild cat is believed to be at large in Liverpool. The animal escaped from its cage on the deck of ship that arrived in the Mersey from South America, and was missed when the vessel berthed in Toxteth Dock. The crew were considerably alarmed when the cage was found to be broken open and empty. A party was instantly organised, and carrying defensive weapons they searched every likely corner of the ship but without success. As a last resort, a large piece meat was placed in the hold. Within twelve hours it had disappeared, probably consumed by the wild cat or carried away to its new lair. The captain of the ship, owing to the savage nature of the creature, felt it his duty to report the matter to the police. They gave advice as to further search, and issued a warning to police along the line of the docks. No trace of the animal has been found, and it is hoped the solution of the mystery will prove to be that the pussy has met an untimely end by falling overboard into the dock.” Luckily the South American small cats are not very interfertile with domestic cats, so even if this escaped cat did breed with local domestic cats, the male and female offspring would be infertile due to mismatched chromosome counts.

This is conspiracy theory. The problem with conspiracy theory is that any attempt to disprove it results in claims of "it's a cover up". Phenomena such as out of place big cats and UFOs attract conspiracy theorists like flies to a corpse. Conspiracy theorists also claim that big cat bodies have been secretly disposed of by mysterious men in vans or that the cats have been shot and secretly buried. There are also publicity seekers who claim to have shot and buried big cats umpteen years ago, but didn't take photos and can't remember where. The fact that there is no material evidence and no independent witnesses points to a hoax, mistake or wishful thinking, but conspiracy theorist claim that it is all part of the cover up. There is, however, a cover-up over what is killing sheep. The main culprit is the domestic dog, but this fact is unpalatable and therefore ignored.

Conspiracy theorists have one unassailable argument - every claim that there is no evidence to back up the conspiracy claim is seen as another part of the (non-existent) conspiracy.

The vast majority of sheep kills are dog attacks. Because dogs are "man's best friend" humans don't like to admit that dogs are little more than fancy-looking wolves and are capable of going rogue. Humans also like to turn a blind eye to the presence of feral dogs and strays that go wild each year. Claims that vets have identified "big cat kills" should be treated with scepticism - most vets will never have seen a big cat kill and are not qualified to make this pronouncement and can only offer an educated guess (the keyword is "guess"). Leopards like to take their kills up trees. So far, no-one has found a sheep carcass in the fork of a nearby oak tree.

As long as dogs are not securely confined at night, there will be livestock killings. The owner may not even be aware that Fido is a playful pet by day and a killer by night. Farmers and dog owners need to accept this fact and tackle the problem of dogs attacking livestock rather than blaming the kills on a big cat and living in denial about Fido's predatory instincts.

Most footprints identified as big cat footprints turn out to be dog pawprints when examined by expert big cat trackers. Enthusiasts with books are not qualified to definitively identify pugmarks. Most vets, never having examined the paws of big cats or seen genuine big cat pugmarks, are also not qualified to make a definitive identification and can only offer an educated guess (the keyword is "guess"). Only trained trackers, big game hunters and safari guides etc are skilled enough to make a positive identification. The presence or absence of claw marks on the prints is often a red herring since it depends on the type of ground. Prints become distorted as wet ground dries. Human nature means that big cat hunters prefer to seek an exotic explanation and refuse to accept a mundane one.

Many british big cat enthusiasts cite the "clean kill", clean state of a carcase, the discarding of intestines or hair plucked from the "kill" as evidence in their favour. The clean state of deer and sheep carcases that are (mis)identified as big cat kills is due to a succession of scavengers. Native carnivores are quickly attracted to the carcases of animals that have died from natural causes or been killed by domestic dogs. Foxes will pluck the hair from the pelt rather than swallow it. The long bones of the legs may be moved some distance from the carcase to avoid competition with other scavengers or even taken back to the fox's earth for cubs. The remaining carcase is further cleaned by smaller scavengers including birds of prey and members of the crow family.

The apparent "clean kill" may be due to an animal dying of disease or natural causes or the evidence of a messy kill being eaten away. Some may even be due to poachers butchering the carcase, followed by scavengers. Anyone who has seen photos of hounds killing foxes (or wildlife documentaries) will see that domestic dogs kill by holding onto the prey e.g. by the muzzle, tail or neck while others disembowel it. Hence a carcase may show bite marks on the neck or throat, but the lethally mauled belly will have been eaten. A single domestic dog may harass a sheep or deer until it is exhausted or stumbles; one or two out-of-control dogs can worry several sheep to death as many sheep farmers can testify.

Lynxes have been spotted in Britain and a young European lynx was captured in Cricklewood. Her behaviour suggested she was an escaped captive. Captive-bred does not mean domesticated or tame, but it does mean accustomed to the sight and sound of humans. A wild lynx would not have rested passively under a bush in the presence of humans; it would have fled as fast and as far from humans as possible. It was slightly underweight and, unused to fending for itself, probably regarded humans as a source of food handouts. Lynxes used to be found in Britain and it is possible that well-intentioned, but misguided, individuals have released them into the wild. An ample rabbit population and, in some areas, small deer means plenty of food for lynxes.

The Scottish puma that was trapped a few decades ago was found to be tame, arthritic and elderly. This means she had been a pet and had probably not fended for herself for long (or at all!) before being trapped. In more remote areas, the policing of Dangerous Wild Animals legislation is difficult and some exotic pets would have escaped notice and not been registered by the owners. At the time, big cats were receiving a lot of attention and a trap was set, the owner probably saw this as an opportunity to dispose of an unwanted exotic pet.

Most of the fuzzy photos of black big cats are fuzzy photos of black domestic cats seen at a distance with no nearby objects to give a true indication of the animal's size. The "head held low" and "long tail" arguments are red herrings. Domestic cats have long tails that they usually carry horizontally behind them (curving downwards and with an upturned tip). When hunting, a domestic cat also carries its head low so it can listen for and scent prey. Some supposed black panthers are black dogs; the lighting, angle and perspective can easily confuse the human eye. In the evening/early morning, there is insufficient light for humans to perceive an animal's true colour, hence we perceive it to be black or grey. Most of the photos that accompany news articles as "evidence" are very clearly domestic cats although die-hard big cat theorists refuse to accept this identification.

The likelihood of populations of hybrid big cats is small due to infertility, but not impossible. A stable population of hybrid big cats is very unlikely. Hybrid big cats do not breed true and will revert to one of the parental types within a couple of generations (this is because only the females are fertile and they must therefore mate with a purebred). The case for hybrids is overstated because it is based on the inability of people to identify what they have seen. Some big cat hunters regularly claim the cats are puma-leopard hybrids. Such hybrids have been bred in captivity, but far from being big cats, the hybrids suffered from dwarfism and died young (without breeding). You can read about Carl Hagenbeck's hybrids or go and see a puma-leopard hybrid in the Rothschild Museum in Tring, England to check for yourself!

Basically, if a big cat can't be identified as lion, tiger, lynx, puma, jaguar or leopard it immediately and erroneously gets called a hybrid. Unless the witness is trained in big cat identification - a zookeeper, safari guide or similar, not simply a person with a picture book - they are not qualified to identify big cats. To further confuse inexpert witnesses, some lions and lionesses appear dappled if seen in the right light (of if seen in dappled shade) and may be misidentified as lion-leopard hybrids. Immature lions and pumas may also be dappled. The ignorance of the general public makes it easy to fool people - a jaguar/leopard x lion hybrid (captive-bred in Chicago) was passed off by a travelling menagerie as a Congolese Spotted Lion in 1908!

Some small cats will hybridise freely and produce fully fertile offspring. Lynx and Bobcats will interbreed. Domestic cats will naturally interbreed with Scottish Wild Cats and Jungle Cats (Swamp Cats [F chaus]). They are claimed to breed naturally with Bobcats, but this is not upheld by DNA analysis. In captivity, domestic cats will interbreed with other small species. All will produce fertile offspring, but none will give rise to 6 ft black monster cats. Among the pantherine big cats, they are only known to hybridise if they are raised together from an early age; if introduced to each other as adults they fight rather than mate.

These are small cats, not big cats. Although some domestic breeds derived from hybrids are larger or taller than the average moggy, they are within the normal size range for domestic cats and are definitely not big cats. They are also wholly domestic in temperament. The statement that a Bengal is a hybrid between a domestic cat and a leopard is false. It is a hybrid between a domestic cat and a small species called the Asian Leopard Cat. The claim that the Savannah (sometimes re-branded as Ashera) is a hybrid between a domestic cat and a wild Cheetah is false. These are hydrids between domestic cats and the Serval.