Do Foxes Have a Good Sense of Smell? Yes — But Hearing Wins

Foxes are frequently described as having 'a keen nose', which is true and slightly misleading. Smell is excellent, but it is not the sense doing most of the work. A fox is best understood as an ear on legs, with a very good nose attached.

Smell: what it is actually for#

A fox's olfactory epithelium carries several hundred million receptor cells — the same order of magnitude as a domestic dog and roughly a hundred times a human's. It also has a functioning vomeronasal organ for detecting pheromones, which is central to the way foxes read each other.

• Communication. Urine marks, faeces on raised objects and secretions from the violet gland on the upper tail advertise identity, sex, status and how recently the animal passed. A fox reading a fence post is reading a guest book.
• Cache management. Foxes bury surplus food in scattered pits and use scent marks to check whether a cache has already been emptied, saving pointless digging.
• Scavenging. Carrion, afterbirth and buried food are found by nose at considerable distance.
• Danger assessment. Human scent on a trap, a bin or a piece of ground is enough to make a fox change its route for days.

Hearing: the sense that catches dinner#

Fox ears are large, mobile and tuned to low frequencies — the rustle and squeak of small rodents rather than high-pitched sounds. A red fox can detect a mouse squeak at around 100 metres and locate a vole moving beneath snow or thick grass precisely enough to strike it blind.

That precision produces the mousing pounce: freeze, cock the head to triangulate, then leap almost vertically and drive both front feet through the cover onto the animal below. Vision plays almost no part; the fox often cannot see the prey at any point before contact. The mechanics are covered in how fast can a fox run.

Vision: built for dusk#

This is why sitting still works when watching foxes, and why scent discipline matters more than camouflage. A fox will often walk past a motionless human it can see perfectly well, and bolt from one it cannot see but can smell.

Touch, and the whiskers#

Foxes have long facial vibrissae and — unusually among canids — sensory hairs on the wrists, used at very close range when the muzzle blocks the view of prey held between the forepaws. There is more in do foxes have whiskers.

The odd one: magnetic sense#

Analysis of thousands of recorded pounces found that foxes are markedly more successful when jumping along a roughly north–south axis, particularly at prey they cannot see. The proposed explanation is that foxes use a magnetic sense as a rangefinder, overlaying a fixed reference on the sound they are hearing. It remains debated, and it is the most interesting unresolved question in fox sensory biology.

How foxes use scent to find cached food#

Cache recovery is the best-studied demonstration of fox olfaction in action, and it produces a counter-intuitive result: memory does more of the work than smell. Foxes return accurately to caches they made days earlier even when scent conditions are poor, and they dig at the right spot without casting around for it. Smell appears to serve a checking function — telling the animal whether the cache is still there before it commits to digging.

That combination is efficient. Spatial memory gets the fox to the right square metre; the nose confirms whether the effort is worth it. It also means a fox raiding your bins is not searching randomly — it is running a remembered circuit of places that have paid off before, which is why removing the reward works and masking the smell does not.