Depending on breed, management and environment, the modern domestic horse has a life expectancy of 25 to 30years. [7] Uncommonly, a few animals live into their 40s and, occasionally, beyond. [8] The oldest verifiable record was " Old Billy", a 19th-century horse that lived to the age of 62. [7] In modern times, Sugar Puff, who had been listed in Guinness World Records as the world's oldest living pony, died in 2007 at age 56. [9] Handbuch der Anatomie der Tiere für Künstler(hosted by the University of Wisconsin Digital Collections) https://uwdc.library.wisc.edu/collections/science/vetanatimgs/ Sequenced horse genome expands understanding of equine, human diseases". Cornell University College of Veterinary Medicine. 2012-08-21. Archived from the original on 2017-10-10 . Retrieved 2013-04-01.

Do You Know How Horses Sleep?". Archived from the original on 22 January 2018 . Retrieved 12 September 2018. Ryder, Erin. "World's Oldest Living Pony Dies at 56". The Horse. Archived from the original on 2014-01-24 . Retrieved 2007-05-31.

The wall is the part of the hoof visible when the foot is placed on the ground. Sole constitutes the greater part of the ground surface of the hoof. Again the frog is a wedge-shaped structure that occupies the angles bounded by the bars and sole. McDonnell, Sue (June 1, 2007). "In Living Color". The Horse. Archived from the original on 2007-09-27 . Retrieved 2007-07-27. A truly wild horse is a species or subspecies with no ancestors that were ever successfully domesticated. Therefore, most "wild" horses today are actually feral horses, animals that escaped or were turned loose from domestic herds and the descendants of those animals. [135] Only two wild subspecies, the tarpan and the Przewalski's horse, survived into recorded history and only the latter survives today. Smith, BP (1996). Large Animal Internal Medicine (Seconded.). St. Louis, MO: Mosby. pp.1086–1087. ISBN 0-8151-7724-0. OCLC 33439780. Meet the smallest horse in the world that's shorter than a greyhound". Guinness World Records. 2019-09-05. Archived from the original on 2021-08-04 . Retrieved 2021-07-06.

You will find two developed mammary glands located at the prepubic region in the horse. If you wish to read detailed anatomical features on mare organs, you may visit the equine anatomy section. Anatomical features of horse heart Valentine, Beth A.; Van Saun, Robert J.; Thompson, Kent N.; Hintz, Harold F. (2001). "Role of dietary carbohydrate and fat in horses with equine polysaccharide storage myopathy". Journal of the American Veterinary Medical Association. 219 (11): 1537–1544. doi: 10.2460/javma.2001.219.1537. PMID 11759989. Archived from the original on 2021-05-11 . Retrieved 2021-05-11. There are also some variations in the endocrine glands of horse. Thyroid gland is located on the most cranial part of the trachea and loosely attached by deep fascia. They are dark brown in color, firm, and highly vascular glands. A narrow fibrous isthmus connects two lateral thyroid lobes.Marklund, L.; M. Johansson Moller; K. Sandberg; L. Andersson (1996). "A missense mutation in the gene for melanocyte-stimulating hormone receptor (MC1R) is associated with the chestnut coat color in horses". Mammalian Genome. 7 (12): 895–899. doi: 10.1007/s003359900264. PMID 8995760. S2CID 29095360.