Dave reproduces by binary fission every 482 years and 5 days (no more, no less), assuming time is still a valid concept. This would mean that the next time Dave will divide is during June 23rd, 2261 (in Earth time). He shrinks with the Heaa he inhabits so that he is not crushed or ripped apart by the notoriously chaotic borders of Heck, Hecc, and Hekk. He is capable of speaking Portuguese fluently, but nobody can hear him without extremely powerful and specialized equipment.
Dave's Heaa is very secure because Dave has a gun, and he will shoot any hostiles that enter his Heaa (even if he has to shoot himself to hit them), causing them to "explode." The gun shrinks with Dave so that Dave is able to use it effectively. Any Heaa other than Dave's is completely safe unless Dave's Heaa is passing by and he decides to raid the Heaa in search of bread that he requires.