This weekend (at 2am on Sunday, October 28th) the clocks in the UK go back by one hour. If you’d forgotten, now’s the time to go and set a reminder for yourself (!), otherwise, I’d like to look in a bit more detail at how the change affects our animals. We change the clocks to give ourselves more daylight at certain times of day – the idea dates back to the early 20th century, and was started in the UK in 1916. However, it can cause problems with our body clocks.


How can this affect animals who don’t use clocks?

While there might be some exceptions for certain primates, it is, of course, true that other than humans, animals do not use clocks. People have often used this argument to “prove” that changing the clocks has no effect on our pets, companions, or livestock. However, that’s a fundamentally flawed point – because the people looking after them DO use clocks! As a result, we do things at different times of day, which might well impact our animals.


How do animals know what time of day it is anyway?

All animals – including humans – have a natural body clock. It’s best studied in mammals, but is also well developed in birds and reptiles. We can think of this body clock as a built-in system to synchronise the animal’s metabolism and sleep/wake cycle to the external world. So, for a diurnal species which is adapted to be active in the day and asleep at night (like humans), metabolic rate falls during the dark, and rises again in the morning. The opposite tends to happen in nocturnal species like hamsters, allowing them to be more active in the dark; whereas crepuscular animals (like cats) have a more complex cycle, making them most active at dawn and dusk.

In fact, we now know that most hormones and indeed most body systems cycle throughout the day, helping the animal to prepare for and recover from its normal evolved lifestyle. This is known as the circadian rhythm and is synchronised by the pineal gland, deep within the brain. At night, the gland produces melatonin, and this seems (through mechanisms that are not well understood!) to promote sleep in diurnal animals, and wakefulness in nocturnal ones. As the day length gradually changes throughout the year, the pineal gland keeps the circadian rhythms in sync with the changing day length.


So what’s the problem?

The problem is that all animals who exhibit circadian changes (which is most, although not quite all) are evolved to cope with a 24-hour day. A “jump” of an hour puts the body clock out of sync with the outside world.


Does this have any effect on our health?

There is some data suggesting that it may – studies in humans have suggested that moving the clocks back may trigger mental health problems, while moving them forward in the spring (which I think is much harder!) leads to an increased risk of accidents, heart attacks, strokes and even miscarriages. Exactly why is not understood, but we need to remember that our body clocks influence every part of our bodies and minds, so it seems logical that messing with them could have a huge range of effects.


So what impact will it have on animals?

This is the big question. At the very least, we should expect our animals to be disconcerted and possibly stressed or disturbed by the change – after all, they’re getting attention, or food, or exercise, or whatever, an hour later than they expect. We should also expect this to be most marked for those animals that are most dependent upon us – pets that live in our homes, and stock that have a strict routine. On the other hand, animals like cats, horses or livestock that are out doing their own thing most of the time will be less severely impacted (and may not even notice!).

That said, some animals will be more directly (and potentially harmfully) affected – those on medications where the time of each dose is critical. Good examples would be diabetic pets on insulin (where even an hour out could potentially destabilise them), or epileptic animals on anti-seizure drugs.


If my animal is affected, what can I do to help?

The best solution is to try and phase in the change gradually – move their mealtime, playtime, medicine time, turnout time, or milking time (delete as appropriate for species!) a little later each day. For example, a 10 or 15 minutes a day change, over a 4-7 day period, rather than in one sudden jump, should minimise the impact.

However, the most important thing to remember is that you will probably be far worse affected than your animals – and you may well be feeling stressed, on edge and irritable… so try not to take it out on them, because they don’t understand what’s happening!