First Quote Added
April 10, 2026
Latest Quote Added
"In any case, abundant evidence indicates that all invertebrates with a brain can experience pain. Like vertebrates, numerous invertebrates produce natural opiates and substance P. These animals include crustaceans (e.g., crabs, lobsters, and shrimps), insects (e.g., fruit flies, locusts, and cockroaches), and mollusks (e.g., octopuses, squids, and snails) [...] Also, crustaceans, insects, and mollusks show less reaction to a noxious stimulus when they receive morphine. For example, morphine reduces the reaction of mantis shrimps to electric shock, praying mantises to electric shock, and land snails to a hot surface."
"Bee-eating Wasps [...] feed their larvae on Hive-bees, whom they catch on the flowers while gathering pollen and honey. If the Wasp who has made a capture feels that her Bee is swollen with honey, she never fails, before stinging her, to squeeze her crop, either on the way or at the entrance of the dwelling, so as to make her disgorge the delicious syrup, which she drinks by licking the tongue which her unfortunate victim, in her death-agony, sticks out of her mouth at full length [...] At the moment of some such horrible banquet, I have seen the Wasp, with her prey, seized by the Mantis: the bandit was rifled by another bandit. And here is an awful detail: while the Mantis held her transfixed under the points of the double saw and was already munching her belly, the Wasp continued to lick the honey of her Bee."
"[I]f all sentient beings have equal moral status and insects are sentient, it would seem that we would be obliged to take insects quite seriously indeed. This is highly counterintuitive. Moreover, if all who have moral status have it equally, then we should right now be very invested in the question of whether insects are sentient. If they are, then we are routinely harming trillions of beings with full, equal moral status—a very serious matter. The commonsense reaction that we need not be so concerned with the question of whether insects are sentient suggests that, if they are, their moral status is less than ours, implying that not all who have moral status have it equally."
"Once, indeed, Harry was caught twirling a cockchafer round, which he had fastened by a crooked pin to a long piece of thread, but then this was through ignorance and want of thought: for as soon as his father told him the poor helpless insect felt as much, or more than he would do, were a knife thrust through his hand, he burst into tears, and took the poor animal home, where he fed him during a fortnight on fresh leaves; and when he was perfectly recovered, turned him out to enjoy liberty and fresh air. Ever since that time, Harry was so careful and considerate, that he would step out of the way for fear of hurting a worm, and employed himself in doing kind offices to all the animals in the neighbourhood."
"Do insects experience pain? Yes. Well actually, this concept has been disputed, but I think recent evidence suggests that they do experience what is defined as pain."
"[H]aving worked out the markers that identify both aspects of consciousness in the vertebrates, we apply these same criteria to the invertebrates, and find that the arthropods (including insects and crabs) and cephalopods (like the octopus) meet many of the criteria for exteroceptive and affective consciousness. This would mean that consciousness evolved simultaneously but independently in the first arthropods and first vertebrates over half a billion years ago."
"Many insects stridulate by rubbing together specially modified parts of their hard integuments. This stridulation generally serves as a sexual charm or call; but it is likewise used to express different emotions [...] anger, terror, jealousy, and love."
"There is much debate as to whether invertebrates can feel pain, although most species show responses to adverse stimuli."
"When a worm is suddenly illuminated and dashes like a rabbit into its burrow—to use the expression employed by a friend—we are at first led to look at the action as a reflex one. The irritation of the cerebral ganglia appears to cause certain muscles to contract in an inevitable manner, independently of the will or consciousness of the animal, as if it were an automaton. But the different effect which a light produced on different occasions, and especially the fact that a worm when in any way employed and in the intervals of such employment, whatever set of muscles and ganglia may then have been brought into play, is often regardless of light, are opposed to the view of the sudden withdrawal being a simple reflex action. With the higher animals, when close attention to some object leads to the disregard of the impressions which other objects must be producing on them, we attribute this to their attention being then absorbed; and attention implies the presence of a mind. Every sportsman knows that he can approach animals whilst they are grazing, fighting or courting, much more easily than at other times. The state, also, of the nervous system of the higher animals differs much at different times, for instance, a horse is much more readily startled at one time than at another. The comparison here implied between the actions of one of the higher animals and of one so low in the scale as an earth-worm, may appear farfetched; for we thus attribute to the worm attention and some mental power, nevertheless I can see no reason to doubt the justice of the comparison."
"Whenever taking a step, always watch for ants and insects. Prohibit the building of fires outside (lest insects be killed) and do not set mountain woods or forests ablaze."
"Life is life's greatest gift. Guard the life of another creature as you would your own because it is your own. On life's scale of values, the smallest is no less precious to the creature who owns it than the largest."
"Even if the probability of arthropods being sentient is considered much lower (e.g. less than 10%), the precautionary principle should be applied, because there are huge numbers of arthropods. At this moment, there are about 1018 terrestrial arthropods (mostly ants) and 1020 marine arthropods (mostly very small copepods as zooplankton). This can be compared with about 1010 humans. So if arthropods happen to be sentient and we erroneously believe they are not, we are neglecting huge amounts of welfare and suffering. When a lot is at stake, the precautionary principle is reasonable."
"Thanks that I can say I have never killed a bird. I would not crush the meanest insect which crawls upon the ground. They have the same right to life that I have, they received it from the same Father, and I will not mar the works of God by wanton cruelty."
"Mental Qualities.—There is little to be said on this head. We have seen that worms are timid. It may be doubted whether they suffer as much pain when injured, as they seem to express by their contortions. Judging by their eagerness for certain kinds of food, they must enjoy the pleasure of eating. Their sexual passion is strong enough to overcome for a time their dread of light. They perhaps have a trace of social feeling, for they are not disturbed by crawling over each other's bodies, and they sometimes lie in contact. According to Hoffmeister they pass the winter either singly or rolled up with others into a ball at the bottom of their burrows.* Although worms are so remarkably deficient in the several sense-organs, this does not necessarily preclude intelligence, as we know from such cases as those of Laura Bridgman; and we have seen that when their attention is engaged, they neglect impressions to which they would otherwise have attended; and attention indicates the presence of a mind of some kind. They are also much more easily excited at certain times than at others."
"I found a dimpled spider, fat and white, On a white heal-all, holding up a moth Like a white piece of rigid satin cloth— Assorted characters of death and blight Mixed ready to begin the morning right, Like the ingredients of a witches' broth A snow-drop spider, a flower like a froth, And dead wings carried like a paper kite. What had that flower to do with being white, The wayside blue and innocent heal-all? What brought the kindred spider to that height, Then steered the white moth thither in the night? What but design of darkness to appall?— If design govern in a thing so small."
""Crush not yonder [ant] as it draggeth along its grain; for it too liveth, and its life is sweet to it." A shadow must there be, and a stone upon that heart, that could wish to sorrow the heart even of an [ant]! Strike not with the hand of violence the head of the feeble; for one day, like the ant, thou mayest fall under the foot thyself! Pity the poor moth in the flame of the taper; see how it is scorched in the face of the assembly!"
"A worm or mollusc that is injured, and perhaps writhing, may be feeling pain but could be showing an automatic response. The change in scientific thinking is that the weight of evidence for some of these animals now indicates that they may be feeling pain [...] Some aspects of the pain system exist in leeches, insects, snails, and swimming sea-slugs. However, we cannot be sure that these animals feel pain, or that they do not feel pain [...] There is a case for some degree of protection for spiders, gastropods and insects."
"To let go from my hand a flea that I have caught is a kinder act than to bestow a dirhem on a man in need. There is no difference between the black earless creature which I release and the Black Prince of Kinda who bound the tiara (on his head). Both of them take precaution (against death); and life is dear to it (the flea), and it passionately desires the means of living."
"In the story of the life of the Buddha, in the early days of the saṃgha the monks had no fixed abode but wandered throughout the year. Eventually, the Buddha instructed monks to cease their peregrinations during the torrential monsoon period in order to prevent the killing of insects and worms while walking on muddy roads."
"[A] lot of insects are parasites or predators that kill other insects. So if we (accidentally, intentionally or indirectly) kill some insects, especially predators, we might save the lives of many other insects. Or stated differently: saving one ladybird might mean killing hundreds of aphids. Second, insects in the wild can have net-negative lives, i.e. short lives with more negative than positive experiences. These are lives not worth living. This is due to their reproductive strategy: a fertile adult insect can lay thousands of eggs. If the insect population does not explode at an extreme exponential rate, it is logically required that almost all of the newborn insects will have to die prematurely. The ways of dying are often extremely negative experiences: coldness, starvation, predation, parasitism,…. If an insect is killed, it prevents the birth of many insects with net-negative lives. So, if most insects face very short lives anyway and die horrible deaths anyway, it is far from clear whether killing insects increases overall future insect suffering. We need much more scientific research to estimate the overall effect of killing insects on global welfare."
"I know that stepping on a crack won't break my parents' bones. However, there is a chance that bugs can suffer, and that their suffering is of immense proportion. We live in either World 1 or World 2. In the coming years, decades, and centuries, we will discover which of these worlds we inhabit. Let's make sure that if (or when) we realize we live in World 2, we are satisfied that we have a plan in place and are able to do all we can to improve the lives of bugs."
"Bees also display optimistic and pessimistic emotional states. In such tests, bees first learned that one stimulus (such as the colour blue) is linked to a sugar reward, while another (such as green) is not. They were then faced with an intermediate stimulus (in this case, turquoise). Intriguingly, they responded to this ambiguous stimulus in a 'glass half full', optimistic manner, if they had encountered a surprise reward (a tiny droplet of sucrose solution) on the way to the experiment. But if they had to suffer through an unexpected, adverse stimulus, they responded in a 'glass half empty' (pessimistic) manner."
"Feeling implies the presence of a mind and a mental experience, [or] consciousness. I have every reason to believe that invertebrates not only have emotions but also the possibility of feeling those emotions."
"I would not enter on my list of friends (Though graced with polish'd manners and fine sense, Yet wanting sensibility) the man Who needlessly sets foot upon a worm. An inadvertent step may crush the snail That crawls at evening in the public path; But he that has humanity, forewarned, Will tread aside, and let the reptile live."
"Among insects, most of the pieces of the evidence required to say that insects feel pain appear in some groups to some extent. However, they do not appear in all groups to the extent which would result in a definitive answer. It would not surprise me to learn that some insects, particularly some of the social insects, would posses [sic] all the pieces of evidence."
"E'en 'plaining flies to thee have spoke, Poor trifles as they be; And oft the spider's web thou'st broke, To set the captive free."
"The wing'd Ichneumon for her embryon young Gores with sharp horn the caterpillar throng. The cruel larva mines its silky course, And tears the vitals of its fostering nurse. While fierce Libellula with jaws of steel Ingulfs an insect-province at a meal; Contending bee-swarms rise on rustling wings And slay their thousands with envenom'd stings."
"During the rest of that day there was no other adventure to mar the peace of their journey. Once, indeed, the Tin Woodman stepped upon a beetle that was crawling along the road, and killed the poor little thing. This made the Tin Woodman very unhappy, for he was always careful not to hurt any living creature; and as he walked along he wept several tears of sorrow and regret. These tears ran slowly down his face and over the hinges of his jaw, and there they rusted. When Dorothy presently asked him a question the Tin Woodman could not open his mouth, for his jaws were tightly rusted together. He became greatly frightened at this and made many motions to Dorothy to relieve him, but she could not understand. The Lion was also puzzled to know what was wrong. But the Scarecrow seized the oil-can from Dorothy's basket and oiled the Woodman's jaws, so that after a few moments he could talk as well as before."This will serve me a lesson," said he, "to look where I step. For if I should kill another bug or beetle I should surely cry again, and crying rusts my jaws so that I cannot speak."Thereafter he walked very carefully, with his eyes on the road, and when he saw a tiny ant toiling by he would step over it, so as not to harm it. The Tin Woodman knew very well he had no heart, and therefore he took great care never to be cruel or unkind to anything."
"[W]e propose that at least one invertebrate clade, the insects, has a capacity for the most basic aspect of consciousness: subjective experience. In vertebrates the capacity for subjective experience is supported by integrated structures in the midbrain that create a neural simulation of the state of the mobile animal in space. This integrated and egocentric representation of the world from the animal's perspective is sufficient for subjective experience. Structures in the insect brain perform analogous functions. Therefore, we argue the insect brain also supports a capacity for subjective experience. In both vertebrates and insects this form of behavioral control system evolved as an efficient solution to basic problems of sensory reafference and true navigation. The brain structures that support subjective experience in vertebrates and insects are very different from each other, but in both cases they are basal to each clade."
"The statements about human nature made by psychologists are of two sorts,—statements about consciousness, about the inner life of thought and feeling, the 'self as conscious,' the 'stream of thought'; and statements about behavior, about the life of man that is left unexplained by physics, chemistry, anatomy and physiology, and is roughly compassed for common sense by the terms 'intellect' and 'character.' Animal psychology shows the same double content."
"Among animals, some learn to speak and sing; they remember tunes, and strike the notes as exactly as a musician. Others, for instance the ape, show more intelligence, and yet can not learn music. What is the reason for this... would it be absolutely impossible to teach the ape a language? I do not think so."
"[W]e must steadily bear in mind the sense in which the term "reasoning" is employed. If we apply this term to the process by which an animal, profiting by experience, adapts his actions to somewhat varying circumstances, there can be no hesitation whatever in giving an affirmative answer to the question. ...But there are no grounds for supposing that in the chicken or the horse there is any development of analysis."
"[T]here is every reason to believe that we were gregarious animals before we became men... And a belief in the eject—some sort of recognition of a kindred consciousness in one's fellow beings—is clearly a condition of gregarious action among animals so highly developed as to be called conscious at all."
"It may not be logical, but to my imagination, it is far more satisfactory to look at the young cuckoo ejecting its foster-brothers, ants making slaves, the larvæ of the Ichneumidæ feeding within the live bodies of their prey, cats playing with mice, otters and cormorants with living fish, not as instincts specially given by the Creator, but as very small parts of one general law leading to the advancement of all organic bodies —Multiply, Vary, let the strongest Live and the weakest Die."
"In general, the form and the structure of the brains of quadrupeds are almost the same as those of the brain of man... with this essential difference, that of all the animals man is the one whose brain is largest, and, in proportion to its mass, more convoluted... then come the monkey, the beaver, the elephant, the dog, the fox, the cat. These animals are most like man, for among them, too, one notes the same progressive analogy in relation to the ' in which Lancisi—anticipating the late M. de la Peyronie—established the seat of the soul. The latter, however, illustrated the theory by innumerable experiments."
"[M]ental activities in other organisms can never be to us objects of direct knowledge... we can only infer their existence from the objective sources supplied by observable activities of such organisms. Therefore all our knowledge of mental activities other than our own really consists of an inferential interpretation of bodily activities—this interpretation being founded on our subjective knowledge of our own mental activities. By inference we project, as it were, the known patterns of our own mental chromograph on what is to us the otherwise blank screen of another mind; and our only knowledge of the processes there taking place is really due to such a projection of our own subjectively. This matter has been well and clearly presented by the late Professor Clifford, who has coined the exceedingly appropriate term eject (in contradistinction to subject and object), whereby to designate the distinctive character of a mind (or mental process) other than our own in its relation to our own. I shall therefore adopt this convenient term, and speak of all our possible knowledge of other minds as ejective."
"[T]he phenomena which constitute the subject-matter of Comparative Psychology... have at least as great a claim to accurate classification as those phenomena of structure which constitute the subject-matter of Comparative Anatomy. ...[W]ithin the last twenty years the facts of animal intelligence have suddenly acquired a new and profound importance, from the proved probability of their genetic continuity with those of human intelligence ...[M]y first object ...amounts merely to passing the animal kingdom in review in order to give a trustworthy account of the grade of psychological development which is presented by each group. My second, and much more important object, is that of considering the facts of animal intelligence in their relation to the theory of Descent. With the exception of Mr. Darwin's admirable chapters on the mental powers and moral sense, and Mr. Spencer's great work on the Principles of Psychology, there has hitherto been no earnest attempt at tracing the principles which have been probably concerned in the genesis of Mind. ...[T]he present volume... has for its more ultimate purpose the laying of a firm foundation for my future treatise on Mental Evolution."
"In no case may we interpret an action as the outcome of the exercise of a higher psychical faculty, if it can be interpreted as the outcome of the exercise of one which stands lower in the psychological scale."
"... we rarely think from first principles, even first principles we ourselves sincerely endorse, but rather from sentiments instilled in us by our culture. Nowhere is this more obvious than in the case of humanity’s moral attitudes toward non-human animals. Even most utilitarians, who by their own ideals ought to consider the suffering of all beings important, are still in fact exceptionally anthropocentric in their attitudes. The insights of Darwin have not yet trickled fully into our moral consciousness, not even among those whose moral views demand it. Such is the heavy momentum of culture, which is reflected in every facet of modern politics and political thought. The anthropocentrism of most political philosophy is, to put it mildly, a massive failure."
"In the case of hermit crabs, we find the relevant behavioral pattern. So, we may infer that, like us, they feel pain. To be sure, they have many fewer neurons. But why should we think that makes a difference to the presence of pain? It didn’t make any difference with respect to the complex pattern of behavior the crabs display in response to noxious stimuli. Why should it make any difference with respect to the cause of that behavior? It might, of course. There is no question of proof here. But that isn’t enough to overturn the inference."
"The chimpanzee and the human share about 99.5 per cent of their evolutionary history, yet most human thinkers regard the chimp as a malformed, irrelevant oddity while seeing themselves as stepping-stones to the Almighty. To an evolutionist this cannot be so. There exists no objective basis on which to elevate one species above another. Chimp and human, lizard and fungus, we have all evolved over some three billion years by a process known as natural selection."
"We should give equal priority to equal interests in general, and to equal suffering in particular. Indeed, it is the rejection of the principle of equal consideration of equal interests that requires justification, since such a rejection faces the burden of identifying a morally relevant criterion that can justify this discrimination."
"[The] notion of the life of an animal having 'no moral purpose,' belongs to a class of ideas which cannot possibly be accepted by the advanced humanitarian thought of the present day—it is a purely arbitrary assumption, at variance with our best instincts, at variance with our best science, and absolutely fatal (if the subject be clearly thought out) to any full realization of animals' rights. If we are ever going to do justice to the lower races, we must get rid of the antiquated notion of a 'great gulf' fixed between them and mankind, and must recognize the common bond of humanity that unites all living beings in one universal brotherhood."
"Two slightly different, but not often clearly distinguished usages of "speciesism" should be noted. But more strictly, it is when the discrimination or exploitation [is defended by means of an appeal to] species that it is speciesist. This usage should perhaps be called strict speciesism."
"If possessing a higher degree of intelligence does not entitle one human to use another for his or her own ends, how can it entitle humans to exploit non-humans for the same purpose?"
"The capacity for suffering and enjoying things is a prerequisite for having interests at all, a condition that must be satisfied before we can speak of interests in any meaningful way. It would be nonsense to say that it was not in the interests of a stone to be kicked along the road by a child. A stone does not have interests because it cannot suffer. Nothing that we can do to it could possibly make any difference to its welfare. A mouse, on the other hand, does have an interest in not being tormented, because mice will suffer if they are treated in this way. If a being suffers, there can be no moral justification for refusing to take that suffering into consideration. No matter what the nature of the being, the principle of equality requires that the suffering be counted equally with the like suffering – in so far as rough comparisons can be made – of any other being. If a being is not capable of suffering, or of experiencing enjoyment or happiness, there is nothing to be taken into account. This is why the limit of sentience [...] is the only defensible boundary of concern for the interests of others."
"It is clear that we have direct ethical obligations to sentient animals; but it is not at all clear that we have direct ethical obligations to entities such as species, or to biological diversity. The burden of proof should thus be on conservationists to show how killing the first to preserve the second can possibly be acceptable from an ethical point of view."
"In contrast with this approach, the view that I want to defend puts human and nonhuman animals, as such, on the same moral footing. That is the sense in which I argued, in Animal Liberation, that "all animals are equal." But to avoid common misunderstandings, I need to be careful to spell out exactly what I mean by this. Obviously nonhuman animals cannot have equal rights to vote and nor should they be held criminally responsible for what they do. That is not the kind of equality I want to extend to nonhuman animals. The fundamental form of equality is equal consideration of interests, and it is this that we should extend beyond the boundaries of our own species. Essentially this means that if an animal feels pain, the pain matters as much as it does when a human feels pain—if the pains hurt just as much. How bad pain and suffering are does not depend on the species of being that experiences it."
"So what is the alternative to traditional anthropocentric ethics? Antispeciesism is not the claim that "All Animals Are Equal", or that all species are of equal value, or that a human or a pig is equivalent to a mosquito. Rather the antispeciesist claims that, other things being equal, equally strong interests should count equally."
"Given our anthropocentric bias, thinking of non-human vertebrates not just as equivalent in moral status to toddlers or infants, but as though they were toddlers or infants, is a useful exercise. Such reconceptualisation helps correct our lack of empathy for sentient beings whose physical appearance is different from "us". Ethically, the practice of intelligent "anthropomorphism" shouldn't be shunned as unscientific, but embraced insofar as it augments our stunted capacity for empathy. Such anthropomorphism can be a valuable corrective to our cognitive and moral limitations."