I've often pondered why some animals make friends.<p>I grew up on a small farm, where we mainly kept sheep. Most of the year the ram would have next to no interest in the yews (female sheep), unless there was some sort of threat - he'd just be off doing his own thing.<p>Once my mum bought a calf as auction as it was so cheap (from memory 20p - most cows are sold in lots of 6, but this was an odd lot and no-one bid) - the calf loved us and wanted to be with us whenever we were in the field (and to be bottle fed), but the rest of the time would hang out with the ram.<p>That September a family brought a pet duck to us as their daughter couldn't take it to university and the parents didn't want to look after it. We said sure, and as soon as they left we put it in the pond. The geese we had started to attack it, and the duck ran out of the pond and hid between the legs of the cow who just happened to be near.<p>And that was it - for the rest of the year the duck, cow and ram were always together - they'd pace up and down the field together and at night the duck would either sleep between the cows legs, or curled up to it, if the cow was seated/lying down.<p>They genuinely seemed to all get a lot from the bond they shared as three 'others'. Sadly a couple of years later, after a few of our chickens were eaten by a fox, my mum tried to put the duck away each night. As she was trying to catch it the cow started stamping to tell her to leave the duck alone, and accidentally stamped on the duck, breaking its leg. We took it to a city farm and 'gifted' it to them - but I am told it made friends with their ducks, though I didn't recognise it when we visited - but I was only about 8 at the time.