How to recognise Otters and what to do and to avoid

What follows is based on over 350 encounters with Otters, most of which took place on the islands off the west coast of Scotland. The comments on behaviour therefore refer to this area. This first article considers how you can distinguish an Otter in the sea from a Seal and what you should do or avoid when watching Otters.

It is strange that Otters are one of Britain’s most popular wild animals, when in most of its range it is mostly active during darkness or twilight but undoubtedly this animal is hugely popular. However, you need to be very lucky to see one in most of the UK, but north-west of the border with Scotland, the situation is different.

Watching a Seal or an Otter?

Unlike England’s Otters which are generally nocturnal freshwater specialists the Otters on the west coast of Scotland and the Hebrides hunt in the sea and are active in daylight. To be clear, these are Eurasian Otters Lutra lutra, not Sea Otters Enhydra lutris that are found off the west coast of the USA.

Otters share their seas with Common and Grey Seals so you will often have to decide whether you are watching a seal or an otter.

This is very easy in calm waters but can be tricky when the water is rough and the wind is shaking your binoculars.  In very calm water, Otters look like a series of 3 bumps, one being the head, another is the middle of the back and the last one is the middle of the tail. The body immediately above the two pairs of legs is just under the water. This is a very characteristic appearance, but disappears as soon as there is any roughness or ripples in the water or if the Otter is swimming vigorously.

When foraging, Otters dive for about 15 seconds (unless nosing about among seaweeds in the shallows), eat on the surface if they have caught a small item (larger ones are brought to land) then dive again. When diving in deep water Otters will often shoot for half their length out of the water when surfacing. This regular diving, re-surfacing, then diving, then re-surfacing often shooting up beyond the surface, is a pattern of behaviour we have not seen in seals. Seals will sometimes breach like a whale, leaping partly or entirely out of the water and will sometimes do it several times in a row, but this is quite unlike the steady, rhythmic diving and surfacing of a foraging Otter. When Otters dive they go down head first, so they arch their backs somewhat to get their head pointing down, and as they dive, many Otters (but not all) flick their tail up as they disappear. Seals don’t have tails. When seals are swimming on the surface and dive, they usually simply sink from view, unless engaged in juvenile play or adult mating or aggressive behaviour.

Seals can often be seen hanging motionless, vertically, with their head out of the water, apparently looking up at the sky but are actually recharging their lungs with oxygen. Otters frequently adopt a similar posture when they have captured a small prey item and they are chewing it.

They are rarely motionless when doing this as they twist and turn in the water, with their head held up to keep the prey in their mouth. A seal in this position is motionless apart from the movement of the water. If you are down at water level and get a good sideways view remember a seal has no neck while an Otter does.

If you hope to see Otters the most important thing you need to remember is that you must keep constantly looking for them in suitable habitat. Walking along, facing your companion while talking and occasionally looking around for something to catch your attention, is unlikely to win you an Otter.

European otters (Lutra lutra), mother with a cub on shoreline, Shetland (Scotland)

Otters’ hearing is good but is compromised by the splashing and gurgling sounds of the sea. However, in calm conditions sound carries an unbelievable distance over water, so talk little, and very quietly. It is best not to take a dog as shouting commands or whistling will soon alert an Otter. Otters’ sense of smell is acute so if the wind is blowing from you (or your dog) to the Otter, it is likely that you won’t see the Otter for long, or even at all so position yourself so your scent is not blowing towards the area you want to watch.

Research has suggested that some populations of Hebridean Otters have a tough time balancing the quality and availability of food with the energy demands of everyday life, especially in winter and when mothers are rearing cubs. Bear in mind that the Otter you are watching may be a mother who needs good foraging to support herself and the family of cubs she needs to feed, so think twice or three times before trying to get that little bit closer for a slightly better view or photograph. Just to glimpse these national treasures is a privilege.

Lee Thickett

Nature observer and otter enthusiast.