Editing Rabbit (section)

===Ears===
[[File:Anatomy and physiology of animals The ear.jpg|thumb|Anatomy of mammalian ear]]
[[File:Holland Lop Ears UpDown.png|thumb|A [[Holland Lop]] resting with one ear up and one ear down. Some rabbits can adjust their ears to hear distant sounds.]]
Within the order of [[Lagomorpha|lagomorphs]], the ears are used to detect and avoid predators.{{sfn|Varga|2013|page=62}} In the family [[Leporidae]], the ears are typically longer than they are wide, and are in general relatively long compared to other mammals.<ref name="CapeHare" /><ref>{{Citation |last1=Bertolino |first1=Sandro |title=Eastern Cottontail Sylvilagus floridanus (J. A. Allen, 1890) |date=2023 |work=Primates and Lagomorpha |pages=67–78 |editor-last=Hackländer |editor-first=Klaus |url=https://link.springer.com/referenceworkentry/10.1007/978-3-030-34043-8_14 |access-date=2024-09-16 |place=Cham |publisher=Springer International Publishing |language=en |doi=10.1007/978-3-030-34043-8_14 |isbn=978-3-030-34042-1 |last2=Brown |first2=David E. |last3=Cerri |first3=Jacopo |last4=Koprowski |first4=John L. |editor2-last=Alves |editor2-first=Paulo C.|url-access=subscription }}</ref>

According to [[Allen's rule]], [[endotherm]]ic animals adapted to colder climates have shorter, thicker limbs and appendages than those of similar animals adapted to warm climates. The rule was originally derived by comparing the ear lengths of ''Lepus'' species across the various climates of North America.<ref>{{cite journal |first=Joel Asaph |last=Allen |authorlink=Joel Asaph Allen |title=The influence of Physical conditions in the genesis of species |journal=Radical Review |year=1877 |volume=1 |pages=108–140 |url=http://people.wku.edu/charles.smith/biogeog/ALLE1877.htm}}</ref> Subsequent studies show that this rule remains true in the Leporidae for the ears specifically,<ref>{{Cite journal |last=Stevenson |first=Robert D. |date=1986 |title=Allen's Rule in North American Rabbits (Sylvilagus) and Hares (Lepus) Is an Exception, Not a Rule |url=https://www.jstor.org/stable/1380884 |journal=Journal of Mammalogy |volume=67 |issue=2 |pages=312–316 |doi=10.2307/1380884 |jstor=1380884 |issn=0022-2372|url-access=subscription }}</ref> in that the surface area of rabbits' and hares' ears are enlarged in warm climates;<ref>{{Cite web |url=https://fieldguide.mt.gov/speciesDetail.aspx?elcode=AMAEB03050 |work=Montana Field Guide |publisher=Montana Natural Heritage Program and Montana Fish, Wildlife and Parks |title=Black-tailed Jackrabbit - Lepus californicus |access-date=24 September 2024}}</ref> the ears are an important structure to aid [[thermoregulation]]<ref name=":1">{{Cite journal|doi=10.1016/0024-3205(71)90161-5 |title=The rabbit ear as a temperature sensor |first1=Matthew J. |last1=Kluger |first2=Richard R. |last2=Gonzalez |first3=John W. |last3=Mitchell |first4=James D. |last4=Hardy |journal=Life Sciences |volume=10 |issue= 15 |date=1 August 1971 |pages= 895–899|pmid=5566134 }}</ref> as well as in detecting predators due to the way the outer, middle, and inner ear muscles coordinate with one another. The ear muscles also aid in maintaining balance and movement when fleeing predators.<ref>{{Cite journal|last=Meyer|first=D. L.|date=1971|title=Single Unit Responses of Rabbit Ear-Muscles to Postural and Accelerative Stimulation|journal=Experimental Brain Research|volume=14|issue=2|pages=118–26|doi=10.1007/BF00234795|pmid=5016586|s2cid=6466476}}</ref>

The [[auricle (anatomy)|auricle]], also known as the pinna, is a rabbit's outer ear.<ref name="Capello 2006">{{Cite journal|last=Capello|first=Vittorio|date=2006|title=Lateral Ear Canal Resection and Ablation in Pet Rabbits|url=http://www.ivis.org/proceedings/navc/2006/SAE/617.pdf?LA=1|journal=The North American Veterinary Conference|volume=20|pages=1711–1713}}</ref> The rabbit's pinnae represent a fair part of the body surface area. It is theorized that the ears aid in dispersion of heat at temperatures above {{convert|30|C|F|abbr=on }}, with rabbits in warmer climates having longer pinnae due to this. Another theory is that the ears function as shock absorbers that could aid and stabilize rabbits' vision when fleeing predators, but this has typically only been seen in hares.<ref name="VellaDonnelly" /> The rest of the outer ear has bent canals that lead to the [[eardrum]] or [[Eardrum|tympanic membrane]].<ref name="Parsons 2018">{{Cite journal|last=Parsons|first=Paige K.|date=2018|title=Rabbit Ears: A Structural Look: ...injury or disease, can send your rabbit into a spin|url=https://rabbit.org/journal/4-11/ear.html|journal=House Rabbit Society}}</ref>

The middle ear, separated by the outer eardrum in the back of the rabbit's skull, contains three bones: the hammer, anvil, and stirrup, collectively called [[ossicles]], which act to decrease sound before it hits the inner ear; in general, the ossicles act as a barrier to the inner ear for sound energy.<ref name="Parsons 2018" />

Inner ear fluid, called [[endolymph]], receives the sound energy. After receiving the energy. The inner ear comprises two parts: the [[cochlea]] that uses sound waves from the ossicles, and the [[vestibular apparatus]] that manages the rabbit's position in regard to movement. Within the cochlea a [[basilar membrane]] contains sensory hair structures that send nerve signals to the brain, allowing it to recognize different sound frequencies. Within the vestibular apparatus three semicircular canals help detect [[angular motion]].<ref name="Parsons 2018" />

==== Thermoregulation ====
[[File:California High Desert Cottontail Resting (cropped).jpg|thumb|The blood flow through the rabbit's ears help with thermoregulation, as seen in this [[desert cottontail]].<ref>{{Cite journal|doi=10.2307/1378969 |journal=Journal of Mammalogy |date=31 August 1973 |volume=54 |issue=3 |title=Acclimatization of Thermoregulation in the Desert Cottontail, Sylvilagus audubonii |last=Hinds |first=David S. |pages=708–728|jstor=1378969 |pmid=4744934 }}</ref>]]
The pinnae, which contain a vascular network and arteriovenous shunts, aid in thermoregulation.<ref name="VellaDonnelly" /> In a rabbit, the optimal body temperature is around {{convert|38.5|-|40.0|C|F|abbr=on }}.<ref>{{cite book |last1=Fayez |first1=I |title=Rabbit production in hot climates |last2=Marai |first2=M |last3=Alnaimy |first3=A |last4=Habeeb |first4=M |publisher=CIHEAM |year=1994 |editor1-last=Baselga |editor1-first=M |location=Zaragoza |pages=33–41 |chapter=Thermoregulation in rabbits |editor2-last=Marai |editor2-first=I.F.M. |chapter-url=http://om.ciheam.org/article.php?IDPDF=95605277}}</ref> If their body temperature exceeds or does not meet this optimal temperature, the rabbit must make efforts to return to [[homeostasis]]. Homeostasis of body temperature is maintained by changing the amount of blood flow that passes through the highly vascularized ears,<ref name=":1" />{{Sfn|Varga|2013|p=12}} as rabbits have few to no [[sweat gland]]s.<ref>{{Cite journal |last1=Oladimeji |first1=Abioja Monsuru |last2=Johnson |first2=Temitope Gloria |last3=Metwally |first3=Khaled |last4=Farghly |first4=Mohamed |last5=Mahrose |first5=Khalid Mohamed |date=January 2022 |title=Environmental heat stress in rabbits: implications and ameliorations |url=https://link.springer.com/10.1007/s00484-021-02191-0 |journal=International Journal of Biometeorology |language=en |volume=66 |issue=1 |pages=1–11 |doi=10.1007/s00484-021-02191-0 |pmid=34518931 |issn=0020-7128|url-access=subscription }}</ref> Rabbits may also regulate their temperature by resting in depressions in the ground, known as forms.<ref>{{Cite journal |last1=Milling |first1=Charlotte R |last2=Rachlow |first2=Janet L |last3=Johnson |first3=Timothy R |last4=Forbey |first4=Jennifer S |last5=Shipley |first5=Lisa A |date=2017-09-01 |title=Seasonal variation in behavioral thermoregulation and predator avoidance in a small mammal |url=http://academic.oup.com/beheco/article/28/5/1236/3861738/Seasonal-variation-in-behavioral-thermoregulation |journal=Behavioral Ecology |language=en |volume=28 |issue=5 |pages=1236–1247 |doi=10.1093/beheco/arx084 |issn=1045-2249}}</ref>