goosebumps

Goosebumps are an involuntary physiological reaction to fear, stress or a drop in environmental temperature. Humans and animals use different mechanisms to regulate the exchange of heat between the environment and themselves. This may include:

Behavioural modifications, for example moving somewhere else

Long-term morphological changes, for example a long-haired dog shedding its winter coat in spring

Autonomic changes in blood flow and sweating

Of course most humans don’t have much hair anymore so fluffing or goosebumps don’t do much to keep them warm, but the physiological reaction is ever present and is a reminder that humans are descended from a much hairier species. Piloerection is also a defense mechanism, in particular with animals more than humans. When an animal feels threatened, piloerection causes the fur or feathers to stick out, make the animal appear much larger and more threatening. Piloerection is an involuntary reaction controlled by the sympathetic nervous system. In humans it can still occur as a response to fear or stress, preparing them for ‘fight or flight’. I think this article was useful in the way that i did not know why humans get goosebumps and i didn't know animals did either.

resources: http://roberta-goli.suite101.com/why-do-humans-and-animals-get-goosebumps-a122041