Liger

The male liger (or female ligress) is a hybrid offspring of a male lion (Panthera leo) and a female tigress (Panthera tigris). The liger/ligress has parents in the same genus but of different species. The liger is distinct from the similar hybrid called the tigon, and is the largest of all known extant felines. They enjoy swimming, which is a characteristic of tigers, and are very sociable like lions. Notably, ligers and ligresses typically grow larger than either parent species, unlike tigons, where are the offspring of a male tiger and female lioness.

The history of lion-tiger hybrids 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. The name "liger", a portmanteau of lion and tiger, was coined by the 1930s. "Ligress" is used to refer to a female liger, on the model of "tigress".

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 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.

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 and ligresses 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."

The liger and ligress has a faint tiger-like striped pattern upon a lionesque tawny background. In addition, it 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, as an example of countershading, the underparts are pale. The specific pattern and color depend upon which subspecies the parents were and how the genes interact in the offspring.

White tigers have been crossed with lions to produce "white" (actually pale golden) ligers and ligresses. In theory, white tigers could be crossed with white lions to produce white, very pale or even stripeless ligers or ligresses. There are no black ligers or ligresses. 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. As blue or Maltese tigers probably no longer exist, gray or blue ligers or ligresses are exceedingly improbable. It is not impossible for a liger or ligress to be white, but it is very rare. The first known white ligers were born in December 2013 at Myrtle Beach Safari in Myrtle Beach, South Carolina to a white male lion and a white female tigress.

The liger or ligress is often believed to be the largest known cat in the world. Males reach a total length of 3 to 3.6 m (9.8 to 11.8 ft), which means that they rival even large male lions and tigers in length. Imprinted genes may be a factor contributing to the large size of ligers and ligresses. 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.

Other big cat hybrids can reach similar sizes; the litigon or litigoness, an extremely rare hybrid of a male lion and a female tigoness, is roughly the same size as the liger or ligress, with a male litigon named Cubanacan (at the Alipore Zoo in India) reaching 363 kg (800 lb). 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 or ligress.

It is sometimes wrongly believed that ligers and ligresses 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 or ligresses over six years old, as in 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 ligeresses 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.

Ligers and ligresses are about the same size as the prehistoric Smilodon populator and American lion.