Auris (pl. Aures)
The equine ear (pinna/auricle) is a highly mobile sensory structure controlled by 16 muscles, allowing 180° of independent rotation. This mobility enables horses to localize sounds with remarkable precision; they can detect frequencies from 55 Hz to 33,500 Hz (compared to humans: 20 Hz to 20,000 Hz) and can hear sounds up to 4 km away. The ear canal (external acoustic meatus) is L-shaped, approximately 5–7 cm deep. The inner ear houses the cochlea (hearing) and vestibular apparatus (balance). Ear position is a primary communication tool: forward ears indicate attention/interest, pinned back ears signal aggression/pain, and rapidly swiveling ears show alertness or anxiety. The inner pinna skin is thin and contains protective hair to prevent debris entry.
The inner ear skin is a common site for aural plaques and ticks. Ear-shy behavior is common and may indicate current or past painful ear conditions. Sedation may be required for thorough ear examination. Avoid clipping the inner ear hair completely; it serves a protective function. The guttural pouches (diverticula of the auditory tubes) communicate with the middle ear and can be a source of ear-related pathology.
White to pink, crusty, depigmented plaques on the inner surface of the pinnae caused by equine papillomavirus (often transmitted by black flies; Simulium spp.). Extremely common (up to 50% of horses i
The spinose ear tick (Otobius megnini) specifically targets the ear canal of horses and other livestock. The larvae and nymphs feed deep in the external ear canal for weeks to months, causing intense
Melanocytic tumors occurring at the base of the ear, within the ear canal, or on the pinna. Part of the widespread melanoma syndrome in aging gray horses. May obstruct the ear canal if large, leading
A rare congenital developmental anomaly (choristoma) where ectopic dental tissue develops at the base of the ear or temporal region. Arises from misplaced dental epithelium (first branchial arch tissu
Resistance to ear handling is one of the most common behavioral complaints. Causes include: aural plaques (most common medical cause), ear ticks, previous ear trauma or rough handling (ear twitching),
FLY PROTECTION: Use fly masks with ear covers to protect against black flies (which transmit papillomavirus causing aural plaques) and other biting insects. Ear bonnets during riding serve the same purpose. GENTLE HANDLING: Never 'ear twitch' a horse (twisting the ear for restraint); this causes pain and lasting ear shyness. If your horse suddenly becomes ear-shy, have your vet examine the ears under sedation to rule out medical causes. INNER EAR HAIR: Don't clip the hair inside the ear canal completely; it protects against debris, insects, and water. Trimming excess hair that extends beyond the ear tip is cosmetic and acceptable. WHEN EAR BEHAVIOR CHANGES: If a normally ear-tolerant horse suddenly becomes head-shy or starts shaking its head, consider: ear ticks (especially in the Southwest), new aural plaques, dental issues, poll pain, or bridle/bit discomfort. Don't just train through it; investigate the cause. TICK CHECKS: In endemic areas, periodically check deep in the ear canal (may need a flashlight) for spinose ear ticks, especially in fall and winter. Your vet can safely remove them with appropriate insecticide.
White to pink, crusty, depigmented plaques on the inner surface of the pinnae caused by equine papillomavirus (often transmitted by black flies; Simulium spp.). Extremely common (up to 50% of horses in some regions). Generally cosmetic and non-painful, but the inner ear skin becomes hypersensitive during active infection, causing ear shyness. There is no consistently effective treatment; the condition is lifelong but benign. Signs include: White to pinkish, flat to slightly raised, crusty plaques on the concave (inner) surface of one or both pinnae; may be single or coalescing; horse may become head-shy or ear-shy due to sensitivity; plaques persist indefinitely; may come and go seasonally; NOT precancerous; horse resists ear handling; occasionally mild flaking
The spinose ear tick (Otobius megnini) specifically targets the ear canal of horses and other livestock. The larvae and nymphs feed deep in the external ear canal for weeks to months, causing intense irritation. Endemic in the southwestern United States and arid regions worldwide. Heavy infestations can cause severe irritation, secondary bacterial infection, and rarely vestibular signs. Signs include: Head shaking; ear rubbing against objects; ear-shy behavior; dropping feed from the mouth; head tilt (severe cases); visible blue-gray nymphs deep in the ear canal (may require otoscope); secondary bacterial otitis; serosanguinous discharge from the ear; may cause temporary hearing issues; heavy infestations can lead to self-trauma
Melanocytic tumors occurring at the base of the ear, within the ear canal, or on the pinna. Part of the widespread melanoma syndrome in aging gray horses. May obstruct the ear canal if large, leading to hearing impairment and secondary infection. Parotid gland melanomas may also extend to involve the base of the ear. Signs include: Dark, firm nodule(s) at the ear base, within the ear canal, or on the pinna; usually slow-growing; may be single or multiple; can obstruct the ear canal causing head tilt, discharge, or hearing loss; part of the systemic melanoma burden in gray horses; may ulcerate; large masses may interfere with bridle/halter fit
A rare congenital developmental anomaly (choristoma) where ectopic dental tissue develops at the base of the ear or temporal region. Arises from misplaced dental epithelium (first branchial arch tissue). Contains tooth-like structures (denticles) within a fluid-filled, epithelium-lined cyst. Usually presents in young horses as a chronically draining tract at the base of the ear that fails to respond to antibiotics. Surgical excision is curative. Signs include: Chronic draining tract at the base of the ear or temporal region in a young horse; intermittent serosanguinous to purulent discharge; non-responsive to antibiotic therapy; firm mass may be palpable; tooth-like structure visible on radiographs; usually unilateral; not painful unless secondarily infected; complete surgical excision is curative with excellent prognosis
Resistance to ear handling is one of the most common behavioral complaints. Causes include: aural plaques (most common medical cause), ear ticks, previous ear trauma or rough handling (ear twitching), guttural pouch disease, dental pain, TMJ dysfunction, poll pain (nuchal bursitis), ear melanomas, and idiopathic hypersensitivity. A thorough examination (may require sedation) should rule out medical causes before attributing to behavioral origin. Signs include: Head raising, pulling away, striking, or becoming aggressive when ears are touched; may resist bridling or haltering; head tossing; reluctance to have fly mask put on; may be unilateral or bilateral; sudden onset suggests new medical issue (tick, infection); gradual onset may suggest progressive condition (plaques, melanoma) or learned behavior from rough handling
The inner ear skin is a common site for aural plaques and ticks. Ear-shy behavior is common and may indicate current or past painful ear conditions. Sedation may be required for thorough ear examination. Avoid clipping the inner ear hair completely; it serves a protective function. The guttural pouches (diverticula of the auditory tubes) communicate with the middle ear and can be a source of ear-related pathology.
FLY PROTECTION: Use fly masks with ear covers to protect against black flies (which transmit papillomavirus causing aural plaques) and other biting insects. Ear bonnets during riding serve the same purpose. GENTLE HANDLING: Never 'ear twitch' a horse (twisting the ear for restraint); this causes pain and lasting ear shyness. If your horse suddenly becomes ear-shy, have your vet examine the ears under sedation to rule out medical causes. INNER EAR HAIR: Don't clip the hair inside the ear canal completely; it protects against debris, insects, and water. Trimming excess hair that extends beyond the ear tip is cosmetic and acceptable. WHEN EAR BEHAVIOR CHANGES: If a normally ear-tolerant horse suddenly becomes head-shy or starts shaking its head, consider: ear ticks (especially in the Southwest), new aural plaques, dental issues, poll pain, or bridle/bit discomfort. Don't just train through it; investigate the cause. TICK CHECKS: In endemic areas, periodically check deep in the ear canal (may need a flashlight) for spinose ear ticks, especially in fall and winter. Your vet can safely remove them with appropriate insecticide.
See the Ears on our interactive 3D horse model. Open 3D Model