Answer: The required percentage is 28.57%.
Step-by-step explanation: Given that at an animal shelter, there are 15 dogs, 12 cats, 3 snakes, and 5 parakeets.
We are to find the percentage by which parakeets are less than dogs.
From the given information, the number of dogs is

the number of parakeets is

And, the total number of animals is

So, the difference of the number of dogs and parakeets is

Therefore, the percentage by which parakeets are less than dogs is

Thus, the required percentage is 28.57%.