Liger

The liger is a hybrid cross between a male lion (Panthera leo) and a tigress (Panthera tigris), hence has parents with the same genus but of different species. It is distinct from the similar hybrid tigon. It is the largest of all cats and extant felines.

The history of ligers dates to at least the early 19th century in Asia. A painting of two liger cubs was made by Michael Isasi (1772−1844). In 1825, G.B. Whittaker made an engraving of liger cubs born in 1824. The parents and their three liger offspring are also depicted with their trainer in a 19th Century painting in the naïve style.

Two liger cubs which had been born in 1837 were exhibited to William IV and to his successor Victoria. On 14 December 1900 and on 31 May 1901, Carl Hagenbeck wrote to zoologist James Cossar Ewart with details and photographs of ligers born at the Hagenbeck's Tierpark in Hamburg in 1897.

In Animal planet and the World of Tigers and lions and tigers (1902–1903), A.H. Bryden described Hagenbeck's "lion-tiger" hybrids:

It has remained for one of the most enterprising collectors and naturalists of our time, Mr Carl Hagenbeck, not only to breed, but to bring successfully to a healthy maturity, specimens of this rare alliance between those two great and formidable felidae, the lion and tiger. The illustrations will indicate sufficiently how fortunate Mr Hagenbeck has been in his efforts to produce these hybrids. The oldest and biggest of the animals shown is a hybrid born on the 11th May, 1897. This fine beast, now more than five years old, equals and even excels in his proportions a well-grown lion, measuring as he does from nose tip to tail 10 ft 2 inches in length, and standing only three inches less than 4 ft at the shoulder. A good big lion will weigh about 400 lb [...] the hybrid in question, weighing as it does no less than 467 lb, is certainly the superior of the most well-grown lions, whether wild-bred or born in a menagerie. This animal shows faint striping and mottling, and, in its characteristics, exhibits strong traces of both its parents. It has a somewhat lion-like head, and the tail is more like that of a lion than of a tiger. On the other hand, it has no trace of mane. It is a huge and very powerful beast.

In 1935, four ligers from two litters were reared in the Zoological Gardens of Bloemfontein, South Africa. Three of them, a male and two females, were still living in 1953. The male weighed 750 lb. and stood a foot and a half taller than a full grown male lion at the shoulder.

Although ligers are more commonly found than tigons today, in At Home In The Zoo (1961), Gerald Iles wrote "For the record I must say that I have never seen a liger, a hybrid obtained by crossing a lion with a tigress. They seem to be even rarer than tigons."

Size and growth

Imprinted genes may be a factor contributing to huge liger size. These are genes that may or may not be expressed on the parent they are inherited from, and that occasionally play a role in issues of hybrid growth. For example, in some dog breed crosses, genes that are expressed only when maternally-inherited cause the young to grow larger than is typical for either parent breed. This growth is not seen in the paternal breeds, as such genes are normally "counteracted" by genes inherited from the female of the appropriate breed.

The tiger produces a hormone that sets the fetal liger on a pattern of growth that does not end throughout its life. The hormonal hypothesis is that the cause of the male liger's growth is its sterility — essentially, the male liger remains in the pre-pubertal growth phase. Male ligers also have the same levels of testosterone on average as an adult male lion. In addition, female ligers also attain great size, weighing approximately 700 lb (320 kg) and reaching 10 feet (3.05 m) long on average, and are often fertile. In contrast, pumapards (hybrids between pumas and leopards) tend to exhibit dwarfism.

Hercules and Sinbad

Jungle Island in Miami is home to a liger named Hercules, the largest non-obese liger, who is recognized by the Guiness Book of World Records as the largest cat on Earth, weighing in at 900 lbs. Hercules was also featured on the Today Show, Good Morning America, Anderson Cooper 360, Inside Edition and in a Maxim magazine article in 2005, when he was only 3 years old and already weighed 408.25 kg (900 lb) at the time. Hercules seems completely healthy and is expected to live a long life. The cat's breeding is said to have been a complete accident. Sinbad, another Liger, was shown on the National Geographic Channel. Sinbad was reported to have the exact weight of Hercules. Hercules and Sinbad belong to the T.I.G.E.R.S. family of animal ambassadors, who put on the "Wild Encounters."`

Longevity

Shasta, a ligress (female liger) was born at the Hogle Zoo in Salt Lake City on May 14, 1948 and died in 1972 at age 24. The 1973 Guinness world records reported an 18-year-old, 798-kg (1,756 lb) male liger living at Bloemfontein zoological gardens, South Africa, in 1888. Valley of the Kings animal sanctuary in Wisconsin had a male liger named Nook who weighed around 550 kg (1,210 lb), and died in 2007, at 21 years old.

Fertility

The fertility of hybrid big cat females is well-documented across a number of different hybrids. This is in accordance with Haldane's rule: in hybrids of animals whose sex is determined by sex chromosomes, if one sex is absent, rare or sterile, it is the heterogametic sex (the one with two different sex chromosomes e.g. X and Y).

According to Wild Cats of the World (1975) by C. A. W. Guggisberg, ligers and tigons were long thought to be sterile: In 1943, however, a fifteen-year-old hybrid between a lion and an 'Island' tiger was successfully mated with a lion at the Munich Hellabrunn Zoo. The female cub, although of delicate health, was raised to adulthood.

Colors

Ligers have a tiger-like striping pattern on a lion-like tawny background. In addition they may inherit rosettes from the lion parent (lion cubs are rosetted and some adults retain faint markings). These markings may be black, dark brown or sandy. The background color may be correspondingly tawny, sandy or golden. In common with tigers, their underparts are pale. The actual pattern and color depends on which subspecies the parents were and on the way in which the genes interact in the offspring.

White tigers have been crossed with lions to produce "white" (actually pale golden) ligers. In theory white tigers could be crossed with white lions to produce white, very pale or even stripeless ligers. A black liger does not actually exist. Very few melanistic tigers have ever been recorded, most being due to excessive markings (pseudo-melanism or abundism) rather than true melanism. No reports of black lions have ever been substantiated. The blue or Maltese Tiger is now unlikely to exist, making gray or blue ligers an impossibility. It is not impossible for a liger to be white, but it is very rare.

Zoo policies

Keeping the two species separate has always been standard procedure. However, ligers have occurred and do occur by accident in captivity. Several AZA zoos are reported to have ligers.

In October 2008 a liger attacked its volunteer handler at an animal sanctuary in Broken Arrow, Oklahoma. The handler subsequently died from his injuries.

In 1995 nineteen lions, tigers and ligers were killed near Lava Hot Springs, Idaho after escaping from a dilapidated game farm where they had been bred. Several additional animals, including three ligers, were captured by Idaho Fish and Game and were transported to other facilities. The game farm, called Ligertown, became the inspiration for Napoleon Dynamite's affinity for the animal in the popular movie which was filmed in nearby Preston, Idaho.