Lagomorpha

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The Lagomorphs, order Lagomorpha, are an order of mammals of which there are two families, Leporidae (hares and rabbits), and Ochotonidae (pikas).

Though members of order Lagomorpha can resemble rodents (order Rodentia), and were classified as a superfamily in that order until the early twentieth century, they have since been considered a separate order. For a time it was common to consider the lagomorphs only distant relatives of the rodents, to whom they merely bore a superficial resemblance; however, genetic studies have since shown that, while still distinct from rodents, they are indeed very closely related after all.

Contents

1 Characteristics
2 Classification
3 Lagomorph hybrids
4 References

Characteristics

Lagomorphs (loģ o-moŕ fs)(Gr. lagos, hare: + morphē, form) differ from rodents in that:

they have four (not two as in rodents) incisors in the upper jaw;
they will only eat vegetation (unlike rodents, who will eat meat and vegetation)
the male's scrotum is in front of the penis;
the penis has no bone (baculum) as does the rodents'; and
they will re-digest first time droppings (called cecotropes) to obtain the most from their plant diet.

They resemble rodents, however, in that their teeth grow throughout their life, thus necessitating constant chewing to keep them from growing too long.

Classification

ORDER LAGOMORPHA
* Family Ochotonidae: pikas
** Genus Ochotona
* Family Prolagidae (extinct)
** Genus Prolagus Sardinian Pika (extinct)
* Family Leporidae: rabbits and hares
** Genus Brachylagus
** Genus Bunolagus
** Genus Caprolagus
** Genus Lepus
** Genus Nesolagus
** Genus Oryctolagus
** Genus Pentalagus
** Genus Poelagus
** Genus ''Pronolagus
** Genus Romerolagus
** Genus Sylvilagus

Lagomorph hybrids

According to a publication in 1911, crosses were made between the common rabbit and the guinea-pig (a rodent) and were exhibited in the Zoological Gardens of Sydney, New South Wales. There have been several claims of rabbit/cavy (guinea pig) crosses since then, but none have been verified.

In "The Variation Of Animals And Plants Under Domestication" Charles Darwin wrote: But from what we hear of the marvellous success in France in rearing hybrids between the hare and rabbit (See Dr. P. Broca's interesting memoir on this subject in Brown-Sequard 'Journ. de. Phys.' volume 2 page 367.), it is possible, though not probable, from the great difficulty in making the first cross, that some of the larger races, which are coloured like the hare, may have been modified by crosses with this animal. Nevertheless, the chief differences in the skeletons of the several domestic breeds cannot, as we shall presently see, have been derived from a cross with the hare [...] The common hare [...] has crossed with the rabbit. (Although the existence of the Leporides, as described by Dr. Broca ('Journal de Phys.' tome 2 page 370), has been positively denied, yet Dr. Pigeaux ('Annals and Mag. of Nat. Hist.' volume 20 1867 page 75) affirms that the hare and rabbit have produced hybrids.)

References

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