If you are comparing them to biological viruses, I'd say yes, there are computer viruses that display that level of learning. There are polymorphic viruses that replicate via email, grabbing bits of text from the host to include in the next round. This is why they can avoid any simple filter based on the text of the message subject. They can also modify the text of their own code to avoid detection by anti-virus scanners. This is one of the reasons anti-virus programs need such frequent updates.
I occasionally monitor the log file for the company firewall. I see continual hits by the slammer virus that was effectively countered last summer. Yet it continues to propagate.
To whatever extent computer viruses are able to "learn," it is in the limit of the algorithm that specifies them. That is, they have this ability put into them from "outside." Therefore, they are not alive.