What Is a Healthy Weight For a Hedgehog?

Healthy adult hedgehogs typically weigh between 1 and 2 lbs in the wild. But there is vast variation, depending on the age and sex of the hog and the time of year. Being under-, or less commonly over-weight can cause big problems for hedgehogs, and the scales aren't always the best way of telling whether a hog is carrying the right amount of body fat. 

So if we want to help, it's important to understand how we can tell whether an individual hog is a healthy weight or not. 

Note: this article deals with wild European hedgehogs in the UK, not African Pygmy hedgehogs kept as pets.

What's a Healthy Weight For a Hedgehog?

Before we look at the "what" of hedgehog weight, let's look at the "why". Why do hedgehogs struggle to maintain a healthy weight? And why is the weight of a hedgehog important?

Why is Hedgehog Weight Important?

Whilst we humans might be embracing body positivity and celebrating physiques of all shapes and sizes, this isn't quite how things work in the animal kingdom. Without the protection of "civilization" and a man-made, built, environment being under- or over-weight can pose serious risks for hedgehogs and all other wild animals. 

Underweight Hedgehogs

There are a whole host of reasons why a skinny hedgehog might be in trouble and in need of help.

Going into Hibernation

The most talked-about hedgehog weight problem is being too thin to survive hibernation. 

A hedgehog in hibernation will not eat for several months. Though the metabolism slows dramatically to preserve energy, a hog that hibernates with insufficient far reserves will not survive the winter. 

Guidelines for a healthy weight to enter hibernation vary wildly from Pat Morris's 450 grams to the 600gms recommended by some rescuers now. 

Coming out of Hibernation

But going into hibernation isn't the only time that weight problems can signal trouble for the hedgehog. 

All hedgehogs lose a considerable amount of weight during hibernation. They are all hungry and dehydrated on rousing in the spring. But a hedgehog who went into hibernation skinny is likely to come out starving if they are lucky enough to survive. 

Orphaned Hoglets

Hoglets can also run into problems from being underweight. Hoglets typically stay with their mother for around six weeks after birth. A hoglet without parental supervision who weighs under 300gms could have been separated from his family too early and may struggle to find the food he needs to survive. 

This can be a problem at any time of year, but it's especially difficult where the orphans are autumn juveniles, the product of late litters, and have very little time to put on weight before winter sets in.

Post Pregnancy

In much the same way, female hedgehogs lose a lot of weight themselves during the process of raising hoglets. Mating, nest building, giving birth, nursing and taking care of hoglets is a labour-intensive business. Males do not help, and the female may lack time to feed herself properly whilst raising a family.

When the baby hedgehogs have gone on their way, the mother's first priority is to put on weight. So she can take on another round of breeding or go into hibernation. If food is scarce when she faces this challenge, she could be in serious trouble. 

A Sign of Other Trouble

A hedgehog could also be underweight due to other underlying health issues. Infections and parasites may inhibit a hedgehog's appetite or ability to digest food. Or they can weaken the hog so that it is unable to forage effectively. 

The hog is then in a vicious circle where its lack of energy will compromise its ability to fight off underlying health problems. 

In this state, a hedgehog needs help fast. Contact your local rescue centre. 

Overweight Hedgehogs

Most wild animals face a daily challenge to secure the food they need to survive. Obesity is rare in nature. And certainly, with hedgehogs, it's far more common for a hog's weight problems to be related to being under- rather than over- weight. 

But overweight hogs do exist, and being overweight can be a real problem for a hedgehog. 

Although overweight hedgehogs are occasionally spotted in the wild, the most common cause of hog obesity is having been kept in captivity. 

Given unlimited access to food, most hogs are programmed to just keep on eating. It makes sense when you don't know where the next meal is coming from. 

If a hog is kept by a rescuer, plenty of food combined with limited exercise can lead to obesity. 

Some hedgehogs in captivity have weighed in at over 5lbs, more than twice the weight of a large, wild hog. 

But why is this a problem? Well, apart from the additional strain that excess weight places on the joints and heart of any animal fat poses particular problems for hedgehogs. 

A hedgehog who is very overweight cannot curl into a tight ball. This will make him vulnerable to predators like foxes or even cats who would not usually be able to penetrate his defences.

Though hogs lose weight with alarming speed in the wild, getting them to slim down when in care can be pretty challenging. 

Having their food restricted seems to cause stress and can lead to other health issues. So if you have a hedgehog in your care, it's best to keep a daily check on their weight and not allow them to exceed the healthy range in the first place. 

Why are So Many Hedgehogs Underweight?

As we've seen, hedgehogs do occasionally become overweight, but in the wild, being too skinny is a far bigger problem for our hedgehog population. 

Hedgehogs will spend all night foraging for food, covering considerable distances to find the insects and other invertebrates that make up their preferred diet. 

But in the modern world, even a whole night of dedicated foraging often doesn't yield the 130 calories or 3 oz of food an adult hedgehog needs to find each night to survive. 

Habitat loss for the hogs and the creatures they eat is the main reason they struggle to find the food they need. You can read more about why our hedgehogs are in trouble here. 

So How Do You Know if a Hedgehog Is a Good Weight?

Rescuers and vets will weigh hedgehogs in their care daily to monitor weight gain or weight loss. It’s often a critical factor in determining how well a hedgehog is doing and whether it is ready to be released into the wild. 

And for any of us who find a hedgehog in the garden who might need our help. Popping him on the scales can be a good first step in determining whether it has weight problems. 

You shouldn’t worry about weighing a hedgehog. As long as you do it carefully the animal will not be harmed - and neither will you.

How To Weigh a Hedgehog

Weighing most wild animals can be a bit of a challenge, but hedgehogs are surprisingly cooperative.

Put on a thick pair of gloves, or use a towel to scoop the hedgehog up. 

If it wasn't in a ball already, it almost certainly will be by the time you have it in your hands (if the hedgehog doesn't curl up, it may well be very sick, so call your local rescue straight away).

Then you can just pop it on the scales and check its weight. The hog is likely to stay curled up and still throughout the whole process. 

Depending on the results of your inspection, you can then decide whether to place the hog carefully back into the wild, keep it with you for food and observation, or call your local rescue centre.

The Bunnell Index

Taking a reading from your scales is a good first step.

You can be pretty sure that:

• A hog that weighs less than 550 gms in October is too thin to hibernate safely.
• A hog that weighs less than 300 gms and is separated from its mother needs help at any time of year. 

But beyond that, weighing alone is by no means a foolproof method of deciding whether a hog is a healthy weight or not. 

This is because, like humans, adult hedgehogs come in a wide range of different sizes. 

Nose to tail, adult wild hedgehogs, can measure anything between 8 and 14 inches. That's a big variation. 

So an 8-inch adult going into hibernation and weighing 550gms would be very comfortably padded. A 14 incher weighing 550gms would be very skinny and have little chance of surviving the winter. 

The scales alone can lead to mistakes: failing to help a large hedgehog, who, though he might be pretty heavy, is actually underweight for his size. Or intervening unnecessarily with a hog that appears to be underweight simply because she has a small frame.

Rescuer and researcher Toni Bunnell PhD looked into this issue in more detail and came up with a method which could give a better indication of whether an individual hog is carrying a healthy amount of fat. Without ever going near the scales. 

She calls her method "The Bunnell Index", and it's pretty simple to apply. 

Take your tightly curled up hedgehog and, with a tape measure, measure it around the middle. Pick a point that falls over its nose. Make a note of the measurement - A. Then repeat the process, measuring right around the length of the hog, head to toe - B 

Then divide the width of your hedgehog A by the length, B. If the number you come up with is 0.8 or above, the hedgehog is carrying enough fat for its size.

Dr Bunnell has tested the index against a wide range of hedgehogs of all sizes and ages. Her method seems pretty reliable and a good alternative to the scales. 

Can You Tell Just By Looking?

Hedgehog rescuers will often make the initial judgement just by the look and feel of the hog. 

This isn't quite as easy as it may at first sound. Whilst it can be easy to get an idea, just by looking, as to whether a cat or dog is seriously under- or over-weight, the picture isn't quite so clear when your patient's body shape is disguised by a cloak of spies. 

But there are ways of telling. A healthy-weight uncurled hedgehog should be roughly tear or raindrop shaped: pointed at the nose end and nicely rounded in the rear. If the tail end of the hedgehog is also pointed, or V-shaped then it's probably underweight. 

Once you have handled a few hedgehogs, you'll also notice that a healthy hog has a sort of soft-firmness to it under the spines. On underweight hogs, the skin and spines get baggy on the frame, and an experienced hedgehog handler will be able to feel this. 

How to Help an Underweight Hedgehog

We've seen that whilst hedgehogs do occasionally get too fat, being underweight is by far the most common weight problem in the hedgehog world. 

Man's destruction of their natural habitat is the main cause of hedgehog hunger. So it's good to know that we can at least be part of the solution. 

There are times when an underweight hedgehog will need to be rescued or overwintered. Or, if there are other health problems, he may need specialist care at a wildlife hospital. 

But much of the time, we can help by ensuring that our gardens are safe places for hedgehogs and providing the food, water and access they need to thrive.

Safety

There are a few key factors to consider when checking that your garden is hedgehog-safe. 

Chemicals.Try to avoid using them in your garden. Insects and invertebrates will eat them, and that way, they will get into the food chain of hedgehogs, birds and anything else that dines from your garden - including you!

Traps. It is surprising what a hedgehog will get trapped in. Just this week, I rescued one from a plastic sack that had been carefully folded and weighted down in our garden shed. If you use garden netting, try to keep it a reasonable distance off the ground, so hedgehogs don't become trapped in it. And just be on the lookout for other places they may have wedged themselves into.

Ponds. A garden pond is excellent for wildlife, but please make sure it's properly wildlife-friendly. Check out our guide here.

Predators. The hedgehog's only natural predator in the UK is the badger. People worry about inviting hedgehogs into their gardens if they have cats and dogs. Usually, there is no need. Most cats and dogs will leave hedgehogs alone. If you have a particularly large aggressive dog, you might want to supervise its outdoor time after dark. 

Gardeners. To keep a hedgehog-safe garden, you need to ensure that gardeners go carefully about their work. Check before you strim, mow long grass, light a bonfire or dig your fork into the compost heap.

Food and Drink.

We would suggest that you leave out hedgehog food all year round. 

Specialist hedgehog food is ideal, but wet or dry dog and cat food can work well too.

Lots of people leave saucers or food on the patio or lawn for hedgehogs. If you want to be sure that it is hedgehogs rather than foxes or cats who are getting the meal, buy a hedgehog feeding station or make your own.

Feeding stations not only keep food away from most other animals in your garden who might eat it, they also keep the food - and the hedgehog - dry and sheltered in bad weather and offer some protection from predators.

A dish of clean, fresh water left just outside the feeding station is essential too.

Hedgehogs will eat all sorts of things, and like humans, can quickly develop a fondness for foods that are not good for them. So It's best to stick to the foods mentioned above.

And, of course, never feed hedgehogs bread and milk; both are bad for them. 

Access

One of the key reasons hedgehogs struggle to find enough natural food is that their paths are often blocked by roads, walls, and fences. So if you want to feed hedgehogs in your garden, creating access - a way for them to get in and out - is essential.

Make a hedgehog highway, and ask your neighbour to do the same. It's easier than you think, Check out our guide here.

Helping Prickles Fatten Up

In this article, we have seen that weight can be a big problem for hedgehogs. Some hedgehogs in captivity may become too fat, but overwhelmingly hedgehog weight problems centre around being undernourished. 

Hedgehogs struggle to find the food they need to survive in the wild now, and being underweight can be life-threatening for many reasons.

Luckily we can help by providing food and water in our gardens. Hedgehogs are in trouble in the UK, with populations still decreasing dramatically in many areas. 

But in some of our towns and cities numbers are stabilising and even starting to show signs of recovery.

And this is down to the food and shelter that hogs are finding in our gardens. So let's keep up the good work.

Thanks for reading! We hope you’ve enjoyed this article and found it useful. If you have suggestions or questions we would love to hear them. Leave us a comment below.