Provide your best answer for the following question. Give ONLY the answer, no other words or explanation.
For example:

Answer: <most likely answer, as short as possible; not a complete sentence, just the answer!>.

The question is: In the past, wild hogs called "javelinas" were seen only in the southern part of New Mexico. Now, javelinas are seen in areas 100 miles further north. What is the most likely cause of this expansion?
Environmental conditions have changed.
Human expansion and habitat fragmentation.