Cephalopods are considered the most intelligent invertebrates, providing important examples of advanced cognitive evolution. The unsuspected leader in invertebrate intelligence is the octopus, which has been proven to have excellent problem-solving ability as well as a range of strategies for evading predators, including changing shape and color. They are highly skilled problem solvers and hunters who use well developed strategies when finding food. They also feel pain.
Squid, another cephalopod group, have a brain structure that is different from other invertebrates in the ocean and instead share complex features similar to the human brain. They can be formidable predators, are very curious about their environment and have the ability to learn new skills and develop the capacity to use tools in order to both protect them from harm and relieve boredom.
Among other invertebrates shown to be sentient are crustaceans. Scientists are divided on whether lobsters feel pain when plunged into boiling water, but agree that they do cringe. The research raises ethical issues as we would certainly condemn plunging a human into water of killing temperatures.
Ants are able to work cooperatively in large groups to forage for food and build nests, which helps them withstand calamities that would wipe another species. Ants accommodate to their environment very well. Research shows that bees can rapidly solve complex mathematical problems. Spiders are among the smallest creatures to possess a proportionately high level of intelligence, particularly the white-mustached portia spiders who have demonstrated special learning skills. Research shows that they hunt with intention.
All in all, we can see that a wide range of animals, vertebrates and invertebrates, are intelligent, self-aware, and engaged in complex relationships within their own communities. Hopefully we will begin to rethink our relationship with the animal kingdom and respect them in their own habitats.
 F. De Waal, “The Brains of the Animal Kingdom,” The Wall Street Journal (22 March 2013); S. Killingsworth, “Why Not Eat Octopus?” The New Yorker (3 October 2014).
 S. Montgomery, The Soul of an Octopus: A Surprising Exploration into the Wonder of Consciousness (New York: Artia Books/Simon & Schuster, 2015).
 D.M. Braun, “The Slightly Disturbing Science of Squid,” National Geographic (12 April 2011).
 J. Dunayer, “The Rights of Sentient Beings: Moving Beyond Old and New Speciesism,” in The Politics of Species: Reshaping Our Relationships with Other Animals, ed. R. Corbey & A. Lanjouw, 27-39 (Cambridge: Cambridge University Press, 2013).
 B. Switek, “Debate Continues: Did Your Seafood Feel Pain?” National Geographic (4 February 2013).
 M. Lihoreau, L. Chittka, & N.E. Raine, “Travel Optimization by Foraging Bumblebees Through Readjustments of Traplines After Discovery of New Feeding Locations,” The American Naturalist 176, no. 6 (2010): 744-757.