Liger

The liger is a hybrid cross between a male lion (Panthera leo) and a female tiger (Panthera tigris).^[1] Thus, it has parents with the same genus but of different species. It is distinct from the similar hybrid tigon. While the Siberian tiger is the largest pure sub-species, ligers are believed to be the largest of all known extant felines.^[2][3][4]

Ligers exist only in captivity or zoo because the habitats of the parental species do not overlap in the wild. Historically, when the Asiatic Lion was prolific, the territories of lions and tigers did overlap and there are legends of ligers existing in the wild. Although ligers share characteristics of both from lion and tiger, they more closely resemble the lion, because of the dominant gene.^[5] Notably, ligers typically grow larger than either parent species, unlike tigons which tend to be about as large as a female tiger and is the cross between a male tiger and a lioness.^[6]

Most ligers suffer from embryonic fatality or premature death,^[7] those that survive are often genetically or physically sterile and therefore unable to reproduce and continue their lineage.^[8]

History

The history of ligers dates to at least the early 19th century in India. In 1798, Étienne Geoffroy Saint-Hilaire (1772–1844) made a colour plate of the offspring of a lion and a tiger.

In 1825, G. B. Whittaker made an engraving of liger cubs born in 1824.^[9] 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 born in 1837 were exhibited to King William IV and to his successor Queen 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 Life and the World of Nature (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.^[10]

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 340 kg (750 lb) and stood a foot and a half (45 cm) 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."^[11]

Size and growth

The liger is often believed to represent the largest known cat in the world.^[2] Males reach a total length of 3 to 3.5 m,^[12][13] meaning they are bigger than large Siberian tiger males.^[14] Imprinted genes may be a factor contributing to huge liger size.^[15] 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.^[16]

As of September 2013 the largest liger ever recorded was known as "Hercules". At 922 pounds (418 kg) and 131 inches (330 cm) in length and measuring 49 inches (120 cm) tall at the shoulder, he was considered the world's largest living feline.^[6]

Other big cat hybrids can reach similar sizes; the litigon, a rare hybrid of a male lion and a female tigon, is roughly the same size as the liger, with a male named Cubanacan (at the Alipore Zoo in India) reaching 363 kg (800 lb).^[17] The extreme rarity of these second-generation hybrids may make it difficult to ascertain whether they are larger or smaller, on average, than the liger.

It is wrongly believed that ligers continue to grow throughout their lives due to hormonal issues. It may be that they simply grow far more during their growing years and take longer to reach their full adult size. Further growth in shoulder height and body length is not seen in ligers over 6 years old, same as both lions and tigers. Male ligers also have the same levels of testosterone on average as an adult male lion, yet are azoospermic in accordance with Haldane's rule. In addition, female ligers may also attain great size, weighing approximately 320 kg (705 lb) and reaching 3.05 m (10 ft) long on average, and are often fertile. In contrast, pumapards (hybrids between pumas and leopards) tend to exhibit dwarfism.

Longevity

Shasta, a ligress (female liger) was born at the Hogle Zoo in Salt Lake City on 14 May 1948 and died in 1972 at age 24.^[18] Valley of the Kings animal sanctuary in Wisconsin had a male liger named Nook who weighed around 550 kg (1,213 lb),^[19] and died in 2007, at 21 years old. Hobbs, a male liger at the Sierra Safari Zoo in Reno, Nevada, lived to almost 15 years of age before succumbing to liver failure and weighed in at 450 kg (992 lb).^[20] This liger was born in 1943 and died in 1960. South Africa still has two ligers at its one zoo at Bloemfontein.^[21]

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, 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, though of delicate health, was raised to adulthood.^[22]

In September 2012, the Russian Novosibirsk Zoo announced the birth of a "liliger", which is the offspring of a liger mother and a lion father. The cub was named Kiara.^[23] In 2013 the same pair of an African lion and a female liger produced three more female cubs.^[24]

Appearance

Ligers have a tiger-like striped pattern that is very faint upon a lionesque 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 colour may be correspondingly tawny, sandy or golden. In common with tigers, their underparts are pale. The actual pattern and colour depends on which subspecies the parents were and on how 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. There are no black ligers. 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. Blue or Maltese Tigers are extremely endangered and rare, and may even no longer exist, but grey or blue ligers are possible, if exceedingly improbable. A liger can possibly be white, but the phenomenon is quite rare.

Genetic defects

Due to being a composition of two separate cat species (lions and tigers), the liger suffers from various genetic defects such as infertility, or the inability to breed.^[25] Amongst the many other genetic defects include vulnerability to diseases and other health problems.^[26]

Zoo policies

Breeding of ligers has been banned in many zoos and animal sanctuaries due to no conservation value of the hybrid, and the risk it poses on the tigress that gives birth to it.^[27] Keeping the two species separate has been standard procedure.^[28]

See also

• Heterosis
• List of portmanteaus
• Panthera hybrid
• Tiger versus lion

References

• This article incorporates text from messybeast.com, which is released under the GFDL.

Further reading

• Peters, G. "Comparative Investigation of Vocalisation in Several Felids" published in German in Spixiana-Supplement, 1978; (1): 1–206.
• Courtney, N. The Tiger, Symbol of Freedom. Quartet Books, London, 1980.

Mammal hybrids, arranged by family Bovidae Beefalo Dzo Sheep–goat hybrid Yakalo Żubroń Camelidae Cama Bukht Huarizo Canidae Coydog Coywolf Jackal–dog hybrid Jackal-wolf hybrid Wolfdog Delphinidae Wholphin Elephantidae Elephant hybrid Equidae Hinny Mule Zebroid Felidae Ashera Bengal Blynx Caraval Chausie Kellas Cat Pumapard Savannah Serengeti cat Leoger Leguar Leopon Liger Liguar Liliger Litigon Lijagulep Marozi Tigon Jaglion Jagger Taliger Tiguar Tigard Jagliger Lipard Tileguard Macropodidae Macropod hybrids Suidae Iron Age pig Mustelidae Polecat-ferret hybrid Polecat-mink hybrid Ursidae Grizzly–polar bear hybrid