Can a human be born again as animal in next life if he lives materialistic life?

Question

I want to know if a human can go back in evolution if he doesn't live spiritually and commit thefts and sins throughout his life

Answer 1

Yes, a human can take birth as an animal.

Man’s fate after death

The human soul (jivatma) after having left the sensual body in which it has been incarcerated, again takes its birth in the material womb, the choice or selection of its next bodily parents being determined by his deeds in his previous existences. O you twice-born one, the Ativahika body, (which is peculiar to man alone) is the body which the soul assumes after physical death and is taken away by the orderlies of Yama (the king of death), after the dissolution of his gross earthly body. O you, the best of the twice-born ones, the same body is taken away by the servants of Yama, along the path over which he wields the uncontrolled sway. This is the specific lot of humanity, as contra-distinguished from his fellow animals. Then he is made to whirl round in the womb of the hell of Sadyati which resembles a Ghata Yantra in structure.

O Brahmana, this world is a world of deeds, whereas the next world is a world where the souls are dealt with according to their deserts. The god of, Death determines the hell to which a soul is to be committed to undergo punishment or to the womb in which he is to be born in his next existence, according to his deeds in the previous life. The god of death witnesses the human souls being poured into the wombs of their mothers in the form of essential air. The warders of Death lead the souls of men to their appointed places in the kingdom of their master. The virtuous they adore, while the souls of the wicked they oppress and the god Citragupta draws up an inventory of the good or evil deeds done by them in life.

The departed soul staying in the Ativahika body, receives the funeral oblations offered to him by his relations in this world and then ascends to the region of the Pretas and assumes an astral shape. Thirst and hunger oppress them at this point of transition in their progress upward and they delightfully partake of the oblations and libations of water offered to them by their friends on this side of life. Without such oblations and offerings, a soul cannot pass from his Ativahika body to the astral plain. Then after a lapse of a full year from the date of his death and after having witnessed the Sapindakarana ceremony done for his welfare, the soul of a man, renounces his Preta body and assumes one (Bhoga-Deha) that makes him capable of enjoying the fruits of his work, which might be either good or bad. Then, having enjoyed the fruits of his deeds done in his previous life, a soul is again cast down by the Law of Karma and the body assumed by him in the time of such enjoyment, is eaten up by the spirits of the night. The soul of a man, who was not wholly free from sin in his mundane existence, first reaps the fruits of the good deeds in paradise and is then committed in the pangs of hell in a body which the souls of the wicked assume. The soul that suffers hell at the outset and is thus purified, rises up to heaven to enjoy the fruits at his preponderant good in life and takes its re-birth, after the appointed time, in a pure and prosperous family. The soul of an otherwise virtuous man, but tinged with the shadow of an accidental sin, suffers penances in order to purge off that much evil and assumes a beautiful shape after the necessary purification. A soul is liberated from hell even when a small residue of the previous karma still exists and takes birth in the wombs of animals.

Agni Purana 369.3-18

Answer 2

Reference to humans living a sinful life being reborn as animals isn't rare.

Here is a list of such cases mentioned in the Devībhāgavatapurāṇa, 9th skandha, 33rd chapter paraphrased.

धर्मराज नमस्तुभ्यं नमस्ते यमुनाग्रज। पाहि मां किङ्करैः सार्धं सूर्यपुत्र नमोऽस्तु ते।।

1. Persons who on being proud of their strength (physical or positional) rebuke their friends with harsh words, are reborn as animals for 3 consecutive births where there are scorched under the sun (which might mean that they are born as animals residing in deserts like camels)
2. Those who refuse to feed guests tormented with hunger & thirst are reborn as birds for 7 consecutive births.
3. Blasphemers are reborn as snakes.
4. Persons who discontinues allowances alloted for brāhmaṇas & religious institutions are reborn as worms feeding upon faeces for 60,000 years.
5. Those who dig water-reservoirs at the site of a dried out pre-existing water-reservoir dug by other persons & claim that the reservoir was built solely by them, are reborn as cattle for a century.
6. Persons who donate a particular thing to a brahmaṇa but then due to change in mind, takes back the gifted article & donates the same to another brāhmaṇa, are reborn as lizards for 7 consecutive births. (N.B This was the fate of the king Nṛga but was liberated by the touch of Srī Kṛṣṇa's feet.)
7. Persons who causes others to eat semen, are reborn as worms for a century.
8. The person who causes a brāhmaṇa to bleed is reborn as a tiger for 7 consecutive births.
9. Those who cheat their friends are reborn as donkeys for 3 consecutive births, & again as a fox for the next 3 consecutive births.
10. Serial killers are reborn as rabbits for 7 consecutive births, as fish for the next 7 births, as mosquitos for the next 7 births, as pigs for the next 3 births & as animals of prey like chicken & deer for the next 7 births. (N.B This was the fate of Vālmikī but was delivered by the grace of Śrī Rāmacandra.)
11. The father who sells his own daughter (as a slave or accepts a bride-price or charges money in order to marry off her with he who gives the payment without her consent) is reborn as a worm who feeds upon the faeces of girls (i.e microbes that cause venereal disease in women) for 60,000 years, as a hunter for the next 7 births, as a pig for the next 3 births, as chicken for the next 7 births, as a frog for the next 7 births, as a leech for the next 7 births & as a crow for the next 7 births.
12. Those who eat food served by a childless widow or a woman who has just taken her ṛtusnāna (customary bath taken after cessation of monthly menstruation), is reborn for 7 consecutive births as a poor washerman afflicted with acne/skin eruptions/tumour/pustules/blotches/pimples/boils/botches/carbuncles/pockmarks caused by pox & as a crow for the next 7 births.
13. Foul-mouthed persons who abuse their masters are reborn as horses for 7 consecutive births.
14. The driver of bullock-carts & people employed under him - if they beat cattle with sticks, then they are reborn as cattle for as many times as there are hairs on the body the beaten cattle.
15. If anybody kills a black snake marked with the symbol of lotus, then that person is reborn as a snake & in the next birth as a human afflicted with ringworm and dies a painful death from snake-bite at a tender age. (N.B Death by snake-bite is considered on par with deaths caused by weapons, drowning, burning, poison & suicide. Scriptures forbid cremation of people who died in these ways.)
16. Those who kill insects & small animals while they were obtaining their food as ordained by nature (example mosquitos & leech while they are sucking blood) are reborn as those insects that were killed by that person, as infidels in their next birth & again as a human (born into the faith) devoid of limbs.
17. Those who kill honeybees for extracting honey are reborn as flies/honeybees.
18. The person who beats a brāhmaṇa or unjustly any person from any other caste is reborn as a pig for 7 births & as a crow for the next 3 births.
19. The monarch who tortures his subjects out of greed is reborn as a scorpion for 7 consecutive births & then as a man devoid of limbs & afflicted with diseases.
20. Those who kill aquatic animals like crocodiles (& fishes) when they rise out spontaneously (on being provoked by baits or naturally) are reborn as those same aquatic animals that were killed.
21. Those who steal silver, cows & clothes belonging to brāhmaṇas & devas are reborn as turtles/tortoises for 3 consecutive births, as a human afflicted with vitiligo the next 3 births, as a human with white patches in the next birth, as a white bird in the next birth & as a human who dies young due to colic or diseases of the blood (like septicemia & blood dysentery) for the next 7 births.
22. Those who steal brass, bronze & bell-metal articles belonging to brāhmaṇas & devas are reborn as horses for 7 consecutive births & then as a human with extra limbs/elephantiasis & diseases of the feet.
23. The brāhmaṇa who lives upon ink (i.e solely as a scribe) or serves infidels are reborn as black animals for 3 consecutive births, as a black goat for the next 3 births & as a palmyra tree for the next 3 births.
24. Those who steal food, crops, tāmbula, āsanas & pillows belonging to brāhmaṇas & devas are reborn for 3 consecutive births as sheep, chicken, monkey & as a short-lived, poor, human afflicted with diseases of the heart & devoid of progeny in successive order.
25. Those who cast sinful eyes upon brahmaṇas & cows (i.e incites infidels to attack them) is reborn for 7 consecutive births as a poor human lacking limbs & having twisted limbs (i.e not only the person lacks limbs, but whatever limbs that are already present are also twisted), devoid of spouse & progeny and then for 3 consecutive births as a vulture, pig, cat & peafowl in successive order.
26. The brāhmaṇa who eats the flesh of turtle/tortoise & other such forbidden flesh (like beef, pork etc) is reborn for 3 consecutive births as a turtle, a pig, a cat & a peafowl in successive order. (N.B With the exception of beef & pork, non-brahmaṇas are permitted by the scriptures to consume meat which are deemed forbidden for brahmaṇas.)
27. Those who steal ghee, oil & other such things (used to create lights) from brāhmaṇas & devas are reborn as fish for 7 consecutive births & then as a rat.
28. Those who steal sweet-smeeling oils, āmalakī (used a an substitute of soap & shampoo in ancient times), fragrances (like sandalwood extract & other such articles used in śṛṅgāra) are reborn as a human emitting foul body odour for 7 births, as a musk-producing deer (which were hunted for extracting deer-musk) for 3 next births & as manthāna (a type of insect or the grass Enteropogon dolichostachyus) for the next 7 births
29. If a powerful person snatches away the ancestral land of others by force, deceit or violence, then that person is reborn as a worm feeding upon faeces for 60,000 years & then as a landless, poor human.

The next chapter states

1. Contract-killers are reborn as manthāna for a hundred births, pigs for next 100 births, for 7 consecutive births as a chicken, foxes & tigers in the successive order, wolves for the next 3 births, frogs for the next 7 births & finally as buffaloes.
2. Those who burn down villages & cities are reborn as a ghostly spirit wandering the earth with fiery face, then for the 7 births as a pigeon feeding upon forbidden food (onions, garlic, carrots, radishes & mushrooms), a human suffering from severe colic & a leper in successive order.
3. The person who whispers slanderous things against others & blasphemous material is reborn as a scorpion for 7 consecutive births, as a snake for the next 7 births, as vajrakīṭa (insects feeding upon stones) for 7 births, as bhasmakīṭa (insects feeding upon ashes) & then as a severely diseased human.
4. Those who break inside others' houses & steal things, cattle, goats & sheep are reborn as diseased cattle for 7 consecutive births, for 3 births as sheep & goats successively & then as a poor, griefstruck human devoid of friends, spouses & always suffering from diseases.
5. Those who kill cattle, elephants, horses & cut off (undried) trees are reborn for 3 births as elephants, horses, cattle & infidels.
6. Those who kill cattle, commit brahmahatyā, kill women, indulge in sex with agamyā women (like one's own biological mother, step-mothers, sisters, step-sisters, daughters, daughters-in-law etc), kill mendicants & cause abortions are reborn as vultures for a thousand births, as pigs for the next 100 births, as crows for the next 7 births, as snakes for the next 7 births, as worms feeding upon faeces for 60,000 years, as cattle for many births & then as a poor leper.

The 35th chapter states

7. Men who copulate with kulaṭas (women who indulge in sex with 2 men) are reborn as sparrows.
8. Men who copulate with Dharṣiṇīs (women who indulge in sex with 3 men) are reborn as crows.
9. Men who copulate with Puṁścalīs (women who indulge in sex with 4 men) are reborn as cuckoos.
10. Men who copulate with veśyās (women who indulge in sex with 5 men) are reborn as wolves.
11. Men who copulate with puṅgīs (women who indulge in sex with 6 men) are reborn as pigs.
12. Men who copulate with mahāveśyās (women who copulate with 7 men) are reborn as the śālmalī (Bombax ceiba) tree.
13. The brāhmaṇa who doesn't worships the earthen śivaliṅga dehoutedly is reborn gfotr 7 births as a carnivorous quadruped & them as a temple-priestin the successive order.
14. The brāhmaṇī who voluntarily copulates with a śūdra is reborn as a crow for a thousand births, for a hundred births as a pig, a fox, a jungle-fowl, a pigeon, a monkey in the successive order, then a caṇḍālī ravished by all, a puṁścalī washerwoman afflicted with yakṣma (hepatitis A) & finally into the oiler-caste afflicted with leprosy.
15. Kulaṭās, dharṣiṇīs, puṁścalīs etc are reborn as worms feeding upon faeces for 1,00,000 years.
16. The kṣatriya & the vaiśya who indulge in sex with a brāhmaṇī, are reborn for 7 births as pigs & goats.
17. One who swears falsely touching a śālagrāmaśilā is reborn as a worm feeding upon faeces for 7 consecutive births.
18. One who swears falsely touching a divine icon is reborn as a worm residing in the household of a brāhmaṇa for 7 consecutive births.
19. One who swears falsely placing his/her right hand upon others is reborn as a snake for 7 consecutive births & then as a brāhmaṇa devoid of Vaidika knowledge (i.e becomes an apostate/atheist)
20. One who swears falsely touching a brāhmaṇa is reborn as predators like tigers for 7 consecutive births & then as a deaf-n-dumb person devoid of spouse, progeny & friends for the next 3 births.
21. A betrayer of friends is reborn as a mongoose for the next 7 births.
22. An ungrateful person is reborn as a rhinoceros for the next 7 births.
23. Those who bear false witness are reborn as frogs for the next 7 births.
24. The brahmaṇas who doesn't observes the daily rites (like sandhyāvandanā), doesn't observes holy vows & criticizes others who give religious advices is reborn as aquatic animals for the nexxt 100 births & then as various sorts of fishes.
25. Those who mock at the wealth of brahmaṇas & religious institutions, are reborn as mice for thre next 7 births, then as various insects, trees, birds & animals.
26. The brāhmaṇa who earns a livelihood by practicing astrology or medicine or by selling things like lac, iron, plant extracts (& other such forbidden for sale by brahmaṇas like alcohol, meat, salt, weapons, poisons etc) are reborn as birds, then for the next 7 births as an astrologer & a doctor in successive order, a milkman, an ironsmith & a dyer of clothes.