As a beekeeper the debate sometimes comes up regarding aggressive vs. defensive behavior. I think bee behavior is better understood than tarantula behavior, primarily because of the massive amount of study that honey bees have seen... Usually the debate is brought back up by a newcomer of the hobby...
Bees never go out of their way to attack you, it is always because of a stimulus that you provide. Some strains are calm enough that you can open up a hive with no smoke and work the bees without much commotion in the hive. Other strains are so defensive that even approaching the hive can prove quite dangerous, and working the bees is nearly impossible. For example a very calm hive can turn incredibly defensive if the hive becomes queenless... I found that out last summer...
I bring this up because in both cases the bees show defensive behavior, just impressively different amounts of it. I think that tarantula behavior can be classified in exactly the same way. Varying degrees of defensive behavior. I think that calling them aggressive would be prescribing them with more intelligence, and a degree of maliciousness which they do not possess.
Edit: There are numerous stimuli that determine even a arthropods level of defensive behavior. For example, working a hive in all black clothes after drinking a cup of coffee while breathing directly on the bees the night after a skunk was scratching the hive all night would bring about a terrible result even from the calmest of hives....
An insect or arachnid may present behavior that seems aggressive to you, or lacking in provocation, but just because you are not aware of the provided stimulus does not mean that it does not exist...
Bees never go out of their way to attack you, it is always because of a stimulus that you provide. Some strains are calm enough that you can open up a hive with no smoke and work the bees without much commotion in the hive. Other strains are so defensive that even approaching the hive can prove quite dangerous, and working the bees is nearly impossible. For example a very calm hive can turn incredibly defensive if the hive becomes queenless... I found that out last summer...
I bring this up because in both cases the bees show defensive behavior, just impressively different amounts of it. I think that tarantula behavior can be classified in exactly the same way. Varying degrees of defensive behavior. I think that calling them aggressive would be prescribing them with more intelligence, and a degree of maliciousness which they do not possess.
Edit: There are numerous stimuli that determine even a arthropods level of defensive behavior. For example, working a hive in all black clothes after drinking a cup of coffee while breathing directly on the bees the night after a skunk was scratching the hive all night would bring about a terrible result even from the calmest of hives....
An insect or arachnid may present behavior that seems aggressive to you, or lacking in provocation, but just because you are not aware of the provided stimulus does not mean that it does not exist...