Why does a rabbit twitch its nose? (Hannah, age 11)

Answer by: Dr Anne McBride - University of Southampton

It is true, the twitch, twitch of a rabbit’s nose is a very obvious characteristic, and very important to its survival.  Not only does it draw air in to fill its lungs and breathe, in the same way as we do, but it also helps the rabbit detect danger, and identify friends and potential mates.

When we sniff/smell something, our nostrils expand, lifting upwards and outwards.  The same thing happens in rabbits, but is more obvious because they are constantly sniffing the air, rather than just breathing it in.  Rabbits have over fifty million receptor cells in their nose, compared to our meagre six million.  These enable rabbits to detect predators well before they may even see them.  This is why, if you want to watch rabbits (or other animals) without being noticed, you should approach downwind from them.  That way, the wind will go past the rabbit before it picks up your scent.

Rabbits, like many other animals, have two types of scent detection cells in their nose.  Olfactory sensory cells detect ordinary airborne odours, while a specialised group, the Jacobson Organ, pick up heavy moisture-borne molecules and pheromones.

Moist air carries more scent.  You may have noticed that flowers smell stronger when the dew has settled in the early morning and evening, and woods smell of vegetation in the damp of autumn.  When rabbits breathe in, their split top lip parts and moistens the air as it passes.  This enhances any scent and helps the rabbit discover more about the ‘smelly’ world around it – who is nearby, friend, foe or female ready to be mated, or any scrumptious food.  As rabbits communicate mainly through scent, a good sniff of each other no doubt is a bit like a long human chat!

Rabbits are prey animals and their acute senses help them stay alive.  The eyes, located on the side of their head and slightly above the mid-line, enable them to see behind and above them; their huge, mobile ears can pick up the slightest sounds, though that constantly whiffling nose is perhaps the most important of all.

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