What is the evolutionary advantage to cats of burying their faeces, and why do the same selection pressures not apply to dogs, which have not evolved this behaviour?

Quote: Take the Laysan albatross. These large, graceful seabirds establish breeding colonies on islands in the Hawaiian archipelago, and recently it emerged that in the Oahu colony over 30 per cent of the nesting pairs consist of two females. Female-female pairings have been observed in other birds, such as California gulls and roseate terns, but never at quite such a high rate. What's more, Lindsay Young from the University of Hawaii found that many of the albatross female-female pairs remain faithful over several years. They engage in mutual preening and even occasionally copulation, and, like female-male pairs, each year they raise a single chick. Both females will have laid a fertilised egg and randomly shunted one aside (Biology Letters, vol 4, p 323). Unquote

Since we have such different faces and body structures compared to dogs, how can they instinctively tell that the two spots on the upper portion of our faces are in fact our eyes, and not, for example, our nostrils?

A couple of weeks ago I was walking in the local woods when I heard a lovely gentle warbling sound. It turned out that it was coming from a blackbird in a nearby tree, who was singing very quietly without opening its beak. It was definitely this bird making the sound, not another one further away. Do birds rehearse their songs before committing themselves to singing out loud? This song was surely not intended to be heard by other birds at any distance.

I've read about some studies with electrodes in the brains of sleeping zebra-finches which have suggested that they 'dream' of singing, but is this kind of 'closed-beak singing' a known behaviour?

I can understand the point of a sting if it doesn't kill the animal in the process of stinging something, however the bee dies after stinging something/thing.

The only reason for this that I can think of is for the benefit of other bees- if an animal gets stung once, they are likely to leave all other bees alone.

Also, does a bee know they are going to die if they sting something?

I have a six month old ginger kitten who gets very anxious if the bathroom door is closed on him. He'll take any opportunity to follow me in, whether I'm washing, brushing my teeth, or, um, using the loo (when I'd prefer to keep him out!) My first thought was that he wanted a drink, but he has easy access to water in the kitchen, and he never drinks while in the bathroom with me. He'll follow me right out again afterwards, and if I do manage to keep him on the outside, he meows pitifully at the door until it's opened.

He doesn't much like other doors being closed, but it's when people go into the bathroom that he gets worried or annoyed (or so it seems to me!)

When I mention my kitten's habit to people, many report that their cats have a tendency to follow then into the bathroom too, even if they are not inclined to follow humans around otherwise.

Apparently it's normal cat behaviour, but I'd quite like to find out why!

When I kept pet mice and offered them cheese they wouldn't touch it but I read an article about mice plagues and what to bait traps with and one of their suggestions was smelly cheese.

A normal healthy humans can maintain constant blood flow to their brain providing that the average arterial blood pressures is between 50 and 150 mmHg. Above 150 mmHg there is a risk that blood flow becomes too high, which can potentially cause a brain haemorrhage.  Below 50mmHg and there is a risk that blood flow will be inadequate to perfuse the brain.

Giraffes can grow to heights of 5m.  I think that the difference in cerebral blood pressure between standing fully erect and bending down to ground level to drink would be over 360mmHg. 

I have heard that giraffes have a system of one way valves in their neck veins to prevent pressure overload in the venous system when bending down to drink but it would be impossible to achieve this with their arteries because the blood has to travel in the direction of the head.  

How do giraffes maintain constant brain blood flow over such a huge range of blood pressures?

How do their cerebral arteries cope with such high pressures without bursting?