Old rat's red tears fears

My son's rat is two-and-a-half years old, which I understand is old for a rat. He's slowed down a bit but otherwise seems well.

- DR DAVID GRANT

We have noticed a red tinge in the corners of his eyes and nostrils. Is this something to be concerned about? Rats do make excellent pets for A span is short-between two and three years.

Middle age is between 12 and 18 months, with old age starting from 18 months.

Your son's rat is considered a senior and at his age will be susceptible to a range of conditions.

The redness you are seeing in the corner of his eyes is often called "red tears". The colour is caused by a pigment called porphyrin, produced by the Harderian glands behind the eyes.

When mixed with tears it produces a red tinge in the eyes and nostrils, from where tears emerge.

A small amount is normal and hardly noticeable, but when it is obvious, it is most commonly associated with stress or illness.