What is Metabolic Bone Disease?

MBD is a calcium deficiency caused by a lack of calcium in the diet.

Why is calcium deficiency so deadly in squirrels?

Calcium does more than build strong bones; it also plays a vital role in all body functions. Every cell in your body contains water plus small amounts of dissolved minerals such as calcium, sodium, magnesium, and potassium. These minerals allow the cells to transmit small electrical signals. Without this cell-to-cell communication, organs can't function: your heart can't beat, your nerves can't transmit impulses; in fact, you would die.

When there isn't enough calcium in your squirrel's diet, his body will dissolve the calcium in his bones and use that instead. This eventually causes his bones to become depleted of calcium. Eventually, there isn't enough calcium left to maintain sufficient calcium in the cellular fluids, and the organs can't function properly. This is what causes the symptoms of MBD: loss of appetite, lethargy, muscle pain, paralysis, seizures, and eventually death. Humans and most other animals don't get this type of severe MBD, partly because their calcium requirement is lower and their bones are bigger, allowing them to store more calcium.

How can I prevent my squirrel from getting MBD?

That's easy:

  • Feed your squirrel a formula that's fortified with vitamins and minerals--like Fox Valley or Esbilac--when she's a baby.
  • Start her on the Healthy Diet at weaning. (See our Instructions for Weaning.)
  • Continue to follow the Healthy Diet for Pet Squirrels to ensure a long, healthy, MBD-free life.

What are the risk factors for MBD?

  1. Feeding a non-recommended formula such as scalded milk, human baby formula, kitten formula, etc. Babies raised on Fox Valley formula from at least 5 weeks old through weaning never seem to get MBD
  2. Weaning too early. We recommend that baby squirrels stay on formula for 14-16 weeks.
  3. Weaning on to a diet that does not contain blocks.

How can I tell if my squirrel has MBD?

The symptoms of MBD include loss of appetite, sleeping more, reluctance to climb or jump, nails getting caught in fabric, squirrel seems achy and doesn't want to be touched, paralysis, and finally seizures. If you see any of these symptoms and your squirrel has any risk factors for MBD, it's best to begin treatment. If the squirrel responds to calcium treatment, that usually means MBD was present.

Note that every case is different. Your squirrel may show all of these symptoms or only one. MBD can come on slowly, with a progression of symptoms from loss of appetite and sleeping a lot, to hind-end weakness, to paralysis, and finally seizures. But it can also come on very suddenly, with the squirrel seeming fine one minute and down with paralysis or seizures the next. Sudden onset is most common in young squirrels.

Is MBD very common?

Unfortunately, MBD is extremely common in captive squirrels. There are a couple of reasons for this. One, rodents have very high calcium requirements compared with other animals, or humans. Two, squirrels are very picky eaters and often won't eat any brand of fortified rat diet. This is why we created Henry's squirrel blocks.

What's the most common age for a squirrel to get MBD?

Based on our observations of hundreds of pet squirrels over the years, MBD can strike at any age. Probably the classic age of onset is around 18 months old, but we've seen it in in squirrels as old as 10 years, and in babies less than 4 months old (always due to improper formula, usually combined with too-early weaning and/or weaning onto the wrong diet).

Can MBD be treated?

Yes! The treatment for MBD is extra calcium, plus fixing the diet. The extra calcium immediately boosts your squirrel's calcium levels, but to actually cure MBD, your squirrel must also rebuild his bones. This means fixing the diet to include all the important vitamins, minerals, and protein. This takes a long time--usually at least 6 months to a year.

The good news is that with prompt emergency treatment and consistent follow-up treatment, most squirrels recover completely. Sometimes older squirrels (>5 years old) respond more slowly, and sometimes not at all.

If you think your squirrel may have MBD, see the Emergency Treatment for MBD