Is there intelligence in nature? Are animals intelligent? In reacting to their environment in a way that allows them to survive, is that an intelligent reaction or an automatic "animalistic" one? How is human intelligence different?
Macaws, parakeets, and parrots eat very specific types of clay every morning. This clay contains antidotes to toxins found in certain kind of fruit they eat. How do they know to eat clay; is this intelligent behavior?
"When a honeybee dies it releases a death pheromone, a characteristic odor that signals the survivors to remove it from the hive. This might seem a supreme final act of social responsibility. The corpse is promptly pushed and tugged out of the hive . . . What happens if a live bee is dabbed with a drop of [this pheromone]? Then, no matter how strapping and vigorous it might be, it is carried "kicking and screaming' out of the hive. Even the queen bee, if she's painted with invisible amounts, will be subjected to this indignity." Would you consider this behavior intelligent or not?
source: http://www.andeanrain.com/itin-macaw.htm
source: Shadows of Forgotten Ancestors | Carl Sagan | pg.163
Intelligence is the wrong word, as it is a very general term that can be applied to any sort of cognitive capability; insects are intelligent, while most likely not in any way self aware. Anyway, this topic has no conclusive general agreement in science or biology (as far as I know), but I believe that it is most prevalently agreed (though observation, not exact testing) that animals (mammals, birds, and reptiles) do have a level of self awareness. Animals do follow instinct as a prime determinant of behavior and life practice, meaning dictates by inhibitions rather than conscious self aware decision. They live their lives according to what their instinctual senses tell them to do, creating a structured system of habitat, mating, etc. for each animal species; this ensures their survival and evolution, while self awareness is a risk as it could lead to rejection of positive and vital natural mechanisms. At the same time there are outliers; freak animals that seemingly
choose to live differently, pioneers of their species that bring it to a new level -- I think these are animals that gain control of their own cognition, wrenching themselves free of instinct (while still using it as a guide, rather than master). I think all animals are self aware, but not to a level where they have any desire to control their own actions, not to a level where they have any reason to, so they follow instinct (as doing so brings them satisfaction anyway).
I remember hearing from a visiting biologist in school that animals follow instinct 99% and reason 1%. While I consider that a bit too far in the terms of absolutist irrationality, it does touch upon the nature of animal behavior. They follow instinct primarily, while still being self aware and reasoning to an extent. Their reasoning is not developed enough to gain control, so it remains a simple passive function of their consciousness; not a master function.
Now, instinct is not just an innate sense. It is not born fully developed in any animal, and must be cultivated by learning. Wolfwood separated the two, but I say they are intertwined. Instinct is simply unconscious inhibitions of the lesser reason, the unconscious self that pulls the strings of the conscious self. These unconscious inhibitions are effected by experience and memory, as well as born innate sense, as such when an animal learns something it is ingrained in it's unconscious mind -- which has complete control over the animal. The animal for the most part does not consciously use the information that it has learned, simply by following instinct; aside from the rare occurrences where an animals conscious self awareness takes control.
Though, I do think that there are also some aspects of animal life which are always at least partially under the control of the self aware creature; primarily social interaction (at least with some species). Biologists can't deny the obvious affection some creatures show for each other, particularly primates, parrots, & dolphins, which is entirely out of the natural "norm" of instinct -- it is not something that is basely "positive" to the thriving and survival of the species, rather a whimsical pleasure of the individual animal. Some species of animals are known to take mates for life, and never take another mate if their mate dies -- an obvious fundamentally irrational concept; this obviously can't be the work of instinct, rather self aware thought, emotion.
So basically I say animals are fundamentally controlled by instinct, while possessing self awareness that does not command their behavior except in some ways, and also feeling emotion and the like (aspects of self awareness). I also say that some species have a greater level of this (this is obvious), such as primates.
Now, humans are, as far as we know, the only species on the planet that is not slave to instinct, but rather controlled mostly by reason (self awareness). Our instinct still exists (though sadly we do not pay attention to it, and I think are destroying it as species), but our reason rules. We are able to tap into our instinct, and should, as using it as a guide can only be positive. Humans, unlike animals, do not heed instinct as a control of their behavior. Some individuals use "instinct" as an excuse for "natural" indulgent behavior (hedonism), or actually become slave to it in a way; but this is not the positive heeding of instinct as animals do, rather it is the choice to indulge in hollow pleasures of inhibition (sex, etc.) -- a conscious choice. Animals do not have sex for pleasure, though they do take pleasure in it -- they do it for the good that is in sex, reproduction. Humans have the capability of reasoning on a greater level, using self awareness for grand aims (such as sex for love), but instead seem to for the most part lower ourselves to the level of animalistic reasoning (sex for pleasure -- unhealthy melding of reason and instinct/inhibition, that twists both). Though that is going is a little off track from the topic, it has to do with instinct vs. reasoning. Humans are controlled by reasoning, intelligence as you put it, but currently seem slave to inhibition even with that; rejection of our nature for hollow aims. Anyway, as humans are animals (that evolved from lower castes of animals) it is only logical to assume that the lower castes that are the same basic type of creature (mammal) will at least have the same aspects of cognition -- just to different and lower/higher degrees. So yes, animals, I am quite sure, are "intelligent."