VLOOKUP Help

I am trying to Edit a Time Sheet for my business but im having Difficulty.

Basically what im trying to do is this:

I want to create a list of Text where each peice of Text is equal to a number, for example:

Col.-------------Col.
A----------------B
Cat-------------10
Dog------------20
Mouse----------30
Chicken--------40
Hampster------50

I then would like to set up a table that allows me to Use a Pulldown list to select either..... Cat, Dog, Mouse, Chicken or Hampster. And once ive made this selection it inputs a Number that corrisponds to that particular choice in another Column

For example

From a Column D, Dropdown list, ive chosen "Cat", now as a result of that, in Column E, Row 2, i would like the number "10" to automatically appear. And so on and so forth.

I have already set up the dropdown list, and it works great, (note: i am using reference from inside the same workbook), however i do not know which function to use,(or how to use it) to generate that Automatic Number.

Thank You in advance for your help
Chris