Very closely connected with the subject of vows and votive offerings is that of the worship of snakes, to which vows are made and offerings dedicated.
In a note on serpent worship in Malabar,  it is stated that "even to-day some corner of the garden of every respectable tarawad  is allotted for snakes. Here a few trees are allowed to grow wild, and under them, on a masonry platform, one or more sculptured granite stones representing hooded serpents (cobras) are consecrated and set up. The whole area is held sacred, and a mud lamp is lighted there every evening with religious regularity. I have seen eggs, milk, and plantains offered in the evening, after the lamp has been lit, at these shrines, to invoke the serpent's aid on particular occasions. Such is the veneration in which these shrines are held that Cherumars (agrestic serfs) and other low caste aborigines, who are believed to pollute by their very approach, are absolutely interdicted from getting within the precincts. Should, however, any such pollute the shrine, the resident snake or its emissary is said to apprise the owner of the defilement by creeping to the very threshold of his house, and remaining there until the Karanavan,  or other managing member of the family promises to have it duly purified by a Brahman."
Concerning snake worship in Malabar, Mr C. Karunakara Menon writes  as follows:--
"The existence of snake groves is said to owe its origin to Sri Parasurama. [According to tradition, Parasurama was an avatar of Vishnu, who destroyed the Kshatriya Rajas, and retired to Gokarnam in Canara. He called on Varuna, the god of water, to give him some land. Varuna caused the sea to recede, and thus the land called Kerala (including Malabar) came into existence. Brahmans were brought from Northern India to colonise the new country, but they ran away from fear of the snakes, of which it was full. Parasurama then brought in a further consignment of Brahmans from the north, and divided the country into sixty-four Brahmanical colonies.] Parasurama advised that a part of every house should be set apart for snakes as household gods. The (snake) groves have the appearance of miniature reserved forests, as they are considered sacred, and there is a strong prejudice against cutting down trees therein. The groves contain a snake king and queen made of granite, and a tower-like structure, made of laterite,  for the sacred snakes. Snakes were, in olden days, considered a part of the property. [Transfer deeds made special mention of the family serpent as one of the articles sold along with the freehold.]
"When a snake is seen inside, or in the neighbourhood of the house, great care is taken to catch it without giving it the least pain. Usually a stick is placed gently on its head, and the mouth of an earthenware pot is shown to it. When it is in, the pot is loosely covered with a cocoanut shell, to allow of free breathing. It is then taken to a secluded spot, the pot is destroyed, and the snake set at liberty. It is considered to be polluted by being caught in this way, and holy water is sometimes poured over it. Killing a snake is considered a grievous sin, and even to see a snake with its head bruised is believed to be a precursor of calamities. Pious Malayalis (natives of Malabar), when they see a snake killed in this way, have it burnt with the full solemnities attendant on the cremation of a high-caste Hindu. The carcase is covered with a piece of silk, and burnt in sandalwood. A Brahman is hired to observe pollution for some days, and elaborate funeral oblations are offered to the dead snake."
In Travancore there was formerly a judicial ordeal by snake-bite. The accused thrust his hand into a mantle, in which a cobra was wrapped up. If it bit him, he was declared guilty, if not innocent.
In connection with snake worship in Malabar, Mr Upendra Pai gives the following details.  Among snakes none is more dreaded than the cobra (Naia tripudians), which accordingly has gathered round it more fanciful superstitions than any other snake. This has led to cobra worship, which is often performed with a special object in view. In some parts of the country, every town or village has its images of cobras rudely carved on stone. These cobra stones, as they are termed, are placed either on little platforms of stone specially erected for them, or at the base of some tree, preferably a holy fig.  On the fifth day of the lunar month Shravana, known as the Nagarapanchami--that is, the fifth day of the nagas or serpents--these stones are first washed; then milk, curds, ghi (clarified butter), and cocoanut water, are poured over them. Afterwards they are decorated with flowers, and offerings are made to them. The cobra stone is also worshipped at other times by those who have no male children, in order to obtain such. But to establish new images of cobras in suitable places is regarded as a surer method of achieving this object. For this certain preliminary ceremonies have to be gone through, and, when once the image has been established, it is the duty of the establisher to see that it is properly worshipped at least once a year, on the Nagarapanchami day. The merit obtained is proportionate to the number of images thus worshipped, so that pious people, to obtain a great deal of merit, and at the same time to save themselves the expense of erecting many stone images, have several images drawn, each on a tiny bit of a thin plate of gold or silver. These images are handed over to some priest, to be kept along with other images, to which daily worship is rendered. In this way, great merit is supposed to be obtained. It is also believed that such worship will destroy all danger proceeding from snakes. The cobra being thus an object of worship, it is a deadly sin to kill or maim it. For the cobra is in the popular imagination a Brahman, and there is no greater sin than that of killing a Brahman. Accordingly, if any one kills a cobra, he is sure to contract leprosy, which is the peculiar punishment of those who have either killed a cobra, or have led to the destruction of its eggs by digging in or ploughing up soil which it haunts, or setting on fire jungle or grass in the midst of which it is known to live and breed.
In a note on snake worship, Mr R. Kulathu Iyer writes as follows: --
"In Travancore there is a place called Mannarsala, which is well known for its serpent worship. It is the abode of the snake king and queen, and their followers. The grove and its premises cover about 16 acres. In the middle of this grove are two small temples dedicated to the snake king and queen. There are also thousands of snakes of granite, representing the various followers of the king and queen. Just to the northern side of the temple there is a house, the abode of the Nampiathy,  who performs pooja (worship) in the temple. In caste he is lower in grade than a Brahmin. The temple has paddy (rice) fields and estates of its own, and also has a large income from various sources. There is an annual festival at this temple, known as Ayilyam festival, which is celebrated in the months of Kanny and Thulam (September and October). A large number of people assemble for worship with offerings of gold, silver, salt, melons, etc. The sale proceeds of these offerings after a festival would amount to a pretty large sum. On the day previous to the Ayilyam festival, the temple authorities spend something like three thousand rupees in feeding the Brahmins. A grand feast is given to nearly three thousand Brahmins at the house of the Nampiathy. On the Ayilyam day, all the serpent gods are taken in procession to the illam (house of the Nampiathy) by the eldest female member of the house, and offerings of neerumpalum (a mixture of rice-flour, turmeric, ghi, water of tender cocoanuts, etc.), boiled rice, and other things, are made to the serpent gods. It is said that the neerumpalum mixture would be poured into a big vessel, and kept inside a room for three days, when the vessel would be found empty. It is supposed that the serpents drink the contents. As regards the origin of this celebrated grove, Mr S. Krishna Iyer, in one of his contributions to the Calcutta Quarterly Review, says that 'the land from Avoor on the south to Alleppy on the north was the site of the Khandava forest celebrated in the Mahabaratha; that, when Arjuna set fire to it, the serpents fled in confusion and reached Mannarasalay, and there prayed to the gods for protection; that thereupon the earth around was miraculously cooled down, and hence the name mun-l-ari-l-sala, the place where the earth was cooled. After the serpents found shelter from the Khandava fire, an ancestress of the Nambiathy had a vision calling upon her to dedicate the groves and some land to the Naga Raja (snake king), and build a temple therein. These commands were obeyed forth-with, and thenceforward the Naga Raja became their family deity.' In the 'Travancore State Manual,' Mr Nagam Iyer, referring to Mannarsala, says that 'a member of this Mannarsala illam married a girl of the Vettikod illam, where the serpents were held in great veneration. The girl's parents, being very poor, had nothing to give in the way of dowry, so they gave her one of the stone idols of the serpent, of which there were many in the house. The girl took care of this idol, and worshipped it regularly. Soon she became pregnant, and gave birth to a male child and a snake. The snake child grew up, and gave rise to a numerous progeny. They were all removed to a spot where the present kavu (grove) is. In this kavu there are now four thousand stone idols representing snake gods.' Such is the origin of this celebrated grove of Central Travancore."
On the bank of the river separating Cranganore from the rest of the Native State of Cochin is the residence of a certain Brahman called the Pampanmekkat (snake guardian) Nambudri, who has been called the high priest of serpent worship. It is recorded  by Mr Karunakara Menon that, "a respectable family at Angadipuram (in Malabar) sold their ancestral house to a supervisor in the Local Fund P. W. D. (Public Works Department). He cut down the snake grove, and planted it up. Some members of the vendor's family began to suffer from some cutaneous complaint. As usual the local astrologer was called in, and he attributed the ailment to the ire of the aggrieved family serpents. These men then went to the Brahmin house of Pampu Mekat. This Namboodri family is a special favourite of the snakes. When a new serpent grove has to be created, or if it is found necessary to remove a grove from one place to another, the ritual is entirely in the hands of these people. When a family suffers from the wrath of the serpents, they generally go to this Namboodri house. The eldest woman of the house would hear the grievances of the party, and then, taking a vessel full of gingelly (Sesamum) oil, and looking into it, would give out the directions to be observed in satisfying the serpents."
Concerning the Pampanmekkat Nambudri, Mr Gopal Panikkar writes  that, "it is said that this Nambudri household is full of cobras, which find their abode in every nook and corner of it. The inmates can scarcely move about without placing their feet upon one of these serpents. Owing to the magic influence of the family, the serpents cannot and will not injure them. The serpents are said to be always at the beck and call of the members of this Nambudri family, and render unquestioned obedience to their commands. They watch and protect the interests of the family in the most zealous spirit."
It is said  that, "every year the Nambudri receives many offerings in the shape of golden images of snakes, for propitiating the serpent god to ward off calamity, or to enlist its aid in the cure of a disease, or for the attainment of a particular object. It is well known that the Nambudri has several hundreds of these images and other valuable offerings, the collection of centuries, amounting in value to over a lakh of rupees. This aroused the cupidity of a gang of dacoits (robbers), who resolved some years ago to ease the Nambudri of a great portion of this treasure. On a certain night, armed with lathies (sticks), slings, torches, and other paraphernalia, the dacoits went to the illam, and, forcibly effecting an entrance, bound the senior Nambudri's hands and feet, and threw him on his breast. This precaution taken, the keys of the treasure-room were demanded, the alternative being further personal injury. To save himself from further violence, the keys were surrendered. The dacoits secured all the gold images, leaving the silver ones severely alone, and departed. But, directly they went past the gate of the house, many snakes chased them, and, in the twinkling of an eye, each of the depredators had two snakes coiled round him, others investing the gang, and threatening, with uplifted hoods and hisses, to dart at them. The dacoits remained stunned and motionless. Meantime, the authorities were communicated with, and the whole gang was taken into custody. It is said that the serpents did not budge an inch until after the arrival of the officers."
Other marvellous stories of the way in which the snakes carry out their trust are narrated.
A section of Ambalavasis or temple servants in Malabar, called Teyyambadis, the members of which dance and sing in Bhagavati temples, perform a song called Nagapattu (song in honour of snakes) in private houses, which is supposed to be effective in procuring offspring. 
In many houses of the Tiyans of Malabar, offerings are made annually to a bygone personage named Kunnath Nayar, and to his friend and disciple, Kunhi Rayan, a Mappilla (Muhammadan). According to the legend, the Nayar worshipped the kite until he obtained command and control over all the snakes in the land. There are Mappilla devotees of Kunnath Nayar and Kunhi Rayan, who exhibit snakes in a box, and collect alms for a snake mosque near Manarghat at the foot of the Nilgiri hills. A class of snake-charmers in Malabar, called Kuravan, go about the country exhibiting snakes. It is considered to be a great act of piety to purchase these animals, and set them at liberty. The vagrant Kakkalans of Travancore, who are said to be identical with the Kakka Kuravans, are unrivalled at a dance called pampatam (snake dance).
The Pulluvans of Malabar are astrologers, medicine-men, and priests and singers in snake groves. According to a legend  they are descended from a male and female servant, who were exiled by a Brahman in connection with the rescuing by the female of a snake which escaped when the Gandava forest was set on fire by Agni, the god of fire. Another legend records how a five-hooded snake fled from the burning forest, and was taken home by a woman, and placed in a room. When her husband entered the room, he found an ant-hill, from which the snake issued forth, and bit him. As the result of the bite, the man died, and his widow was left without means of support. The snake consoled her, and devised a plan, by which she could maintain herself. She was to go from house to house, and cry out, "Give me alms, and be saved from snake-poisoning." The inmates would give alms, and the snakes, which might be troubling them, would cease to annoy. For this reason, the Pulluvas, when they go with their pot-drum (pulluva kudam) to a house, are asked to play, and sing songs which are acceptable to the snake gods, in return for which they receive a present of money. A Pulluvan and his wife preside at the ceremony called Pamban Tullal, which is carried out with the object of propitiating the snake gods. Concerning this ceremony, Mr L. K. Anantha Krishna Iyer writes as follows :--
"A pandal (booth) supported by four poles driven into the ground is put up for the purpose, and the tops of the poles are connected with a network of strings, over which a silk or red cloth is spread to form a canopy. The pandal is well decorated, and the floor below it is slightly raised and smoothed. A hideous figure of the size of a big serpent is drawn in rice-flour, turmeric (Curcuma longa), kuvva(Curcuma angustifolia), powdered charcoal, and a green powder. These five powders are essential, for their colours are visible on the necks of serpents. Some rice is scattered on the floor and on the sides, and ripe and green cocoanuts are placed on a small quantity of rice and paddy (unhusked rice) on each side. A puja for Ganapathi (the elephant god) is performed, to see that the whole ceremony terminates well. A good deal of frankincense is burned, and a lamp is placed on a plate, to add to the purity, sanctity, and solemnity of the occasion. The members of the house go round the pandal as a token of reverence, and take their seats close by. It often happens that the members of several neighbouring families take part in the ceremony. The women, from whom devils have to be cast out, bathe and take their seats on the western side, each with a flower-pod of the areca palm. The Pulluvan, with his wife or daughter, begins his shrill musical tunes (on serpents), vocal and instrumental alternately. As they sing, the young female members appear to be influenced by the modulation of the tunes and the smell of the perfumes. They gradually move their heads in a circle, which soon quickens, and the long locks of hair are soon let loose. These movements appear to keep time with the Pulluvan's music. In their unconscious state, they beat upon the floor, and wipe off the figure drawn. As soon as this is done, they go to a serpent grove close by, where there may be a few stone images of serpents, before which they prostrate themselves. They now recover their consciousness, and take milk, water of the green cocoanut, and plantain fruits, and the ceremony is over."
In connection with the Pamban Tullal, Mr Gopal Panikkar writes  that "sometimes the gods appear in the bodies of all these females, and sometimes only in those of a select few, or none at all. The refusal of the gods to enter into such persons is symbolical of some want of cleanliness in them; which contingency is looked upon as a source of anxiety to the individual. It may also suggest the displeasure of these gods towards the family, in respect of which the ceremony is performed. In either case, such refusal on the part of the gods is an index of their ill-will or dissatisfaction. In cases where the gods refuse to appear in any one of those seated for the purpose, the ceremony is prolonged until the gods are so propitiated as to constrain them to manifest themselves. Then, after the lapse of the number of days fixed for the ceremony, and, after the will of the serpent gods is duly expressed, the ceremonies close."
Sometimes, it is said, it may be considered necessary to rub away the figure as many as one hundred and one times, in which case the ceremony is prolonged over several weeks. Each time that the snake design is destroyed, one or two men, with torches in their hands, perform a dance, keeping step to the Pulluvan's music. The family may eventually erect a small platform or shrine in a corner of their grounds, and worship at it annually. The snake deity will not, it is believed, manifest himself if any of the persons or articles required for the ceremony are impure, e.g., if the pot-drum has been polluted by the touch of a menstruating female. The Pulluvan, from whom a drum was purchased for the Madras Museum, was very reluctant to part with it, lest it should be touched by an impure woman. In addition to the pot-drum, the Pulluvans play on a lute with snakes painted on the reptile skin, which is used in lieu of parchment. The skin, in a specimen which I acquired, is apparently that of the big lizard Varanus bengalensis. The lute is played with a bow, to which a metal bell is attached.
In the "Madras Census Report," 1871,  Surgeon-Major Cornish states that there is a place near Vaisarpadi, close to Madras, in which the worship of the living snakes draws crowds of votaries, who make holiday excursions to the temple, generally on Sundays, in the hope of seeing the snakes, which are preserved in the temple grounds; and, he adds, probably as long as the desire of offspring is a leading characteristic of the Indian people, so long will the worship of the serpent, or of snake-stones, be a popular cult. He describes further how, at Rajahmundry in the Telugu country, he came across an old ant-hill by the side of a public road, on which was placed a stone representing a cobra, and the ground all round was stuck over with pieces of wood carved very rudely in the shape of a snake. These were the offerings left by devotees at the abode taken up by an old snake, who would occasionally come out of his hole, and feast on the eggs and ghi (clarified butter) left for him by his adorers. Around this place he saw many women who had come to pray at the shrine. If they chanced to see the cobra, the omen was interpreted favourably, and their prayers for progeny would be granted.
Concerning snake worship in the Tamil country, Mr W. Francis writes as follows :--
"A vow is taken by childless wives to install a serpent (nagapratishtai), if they are blessed with offspring. The
ceremony consists in having a figure of a serpent cut in a stone slab, placing it in a well for six months, giving it life
(pranapratishtai) by reciting mantrams and performing other ceremonies over it, and then setting it up under a pipal tree (Ficus religiosa), which has been married to a margosa (Melia Azadirachta). Worship, which consists mainly in going round the tree 108 times, is then performed to it for the next forty-five days. Similar circumambulations will also bring good luck in a general way, if carried out subsequently."
It is further recorded by Mr F. R. Hemingway  that, "Brahmans and the higher Vellalans think that children can be obtained by worshipping the cobra. Vellalans and Kallans perform the worship on a Friday. Among the Vellalans, this is generally after the Pongal festival. The Vellalans make an old woman cry aloud in the backyard that a sacrifice will be made to the cobra next day, and that they pray it will accept the offering. At the time of sacrifice, cooked jaggery (crude sugar) and rice, burning ghi in the middle of rice-flour, and an egg, are offered to the cobra, and left in the backyard for its acceptance. The Pallis annually worship the cobra by pouring milk on an ant-hill, and sacrificing a fowl near it. Valaiyans, Pallans, and Paraiyans sacrifice a fowl in their own backyards."
In the Tamil country, children whose birth is attributed to a vow taken by childless mothers to offer a snake cut on a stone slab, sometimes have a name bearing reference to snakes given to them, i.e., Seshachalam,  Seshamma, Nagappa, or Nagamma. Naga, Nagasa, or Nageswara, occurs as the name of a totemistic exogamous sept or gotra of various classes in Ganjam and Vizagapatam. In the Odiya caste of farmers in Ganjam, members of the Nagabonso sept claim to be descendants of Nagamuni, the serpent rishi. Nagavadam (cobra's hood) is the name of a subdivision of the Tamil Pallis, who wear an ornament called nagavadam, representing a cobra, in the dilated lobes of the ears.
Ant (i.e., white-ant, Termes) hills, which have been repeatedly referred to in this chapter, are frequently inhabited by cobras, and offerings of milk, fruit, and flowers are consequently made to them on certain ceremonial occasions. Thus it is recorded,  by the Rev. J. Cain that when he was living in Ellore Fort in the Godavari district, in September, 1873, "a large crowd of people, chiefly women and children, came in, and visited every white-ant hill, poured upon each their offerings of milk, flowers, and fruit, to the intense delight of all the crows in the neighbourhood. The day was called the Nagula Chaturdhi--Chaturdhi, the fourth day of the eighth lunar month--and was said to be the day when Vasuki, Takshaka, and the rest of the thousand Nagulu were born to Kasyapa Brahma by his wife Kadruva.  The other chief occasions when these ant-hills are resorted to are when people are affected with earache or pains in the eye, and certain skin diseases. They visit the ant-hills, pour out milk, cold rice, fruit, etc., and carry away part of the earth, which they apply to the troublesome member, and, if they afterwards call in a Brahman to repeat a mantra or two, they feel sure the complaint will soon vanish. Many parents first cut their children's hair near one of these hillocks, and offer the first fruits of the hair to the serpents residing there."
The colossal Jain figure of Gomatesvara, Gummatta, or Gomata Raya, at Sravana Belgola in Mysore,  is represented as surrounded by white-ant hills, from which snakes are emerging, and with a climbing plant twining itself round the legs and arms.
On the occasion of the snake festival in the Telugu country, the Boya women worship the Nagala Swami (snake god) by fasting, and pouring milk into the holes of white-ant hills. By this a double object is fulfilled. The ant-hill is a favourite dwelling of the cobra, and was, moreover, the burial-place of Valmiki, from whom the Boyas claim to be descended. Valmiki was the author of the Ramayana, and is believed to have done penance for so long in one spot that a white-ant hill grew up round him. On the Nagarapanchami day, Lingayats worship the image of a snake made of earth from a snake's hole with offerings of milk, rice, cocoanuts, flowers, etc. During the month Aswija, Lingayat girls collect earth from ant-hills, and place it in a heap at the village temple. Every evening they go there with wave-offerings, and worship the heap. At the Dipavali festival,  the Gamallas (Telugu toddy-drawers) bathe in the early morning, and go in wet clothes to an ant-hill, before which they prostrate themselves, and pour a little water into one of the holes. Round the hill they wind five turns of cotton thread, and return home. Subsequently they come once more to the ant-hill with a lamp made of flour paste. Carrying the light, they go three or five times round the hill, and throw split pulse (Phaseolus Mungo) into one of the holes. On the following morning they again go to the hill, pour milk into it, and snap the threads wound round it.
The famous temple of Subramanya in South Canara is said to have been in charge of the Subramanya Stanikas (temple servants), till it was wrested from them by the Shivalli Brahmans. In former times, the privilege of sticking a golden ladle into a heap of food piled up in the temple on the Shasti day is said to have belonged to the Stanikas. They also brought earth from an ant-hill on the previous day. Food from the heap, and some of the earth, are received as sacred articles by devotees who visit the sacred shrine.
At the Smasanakollai festival in honour of the goddess Ankalamma at Malayanur, some thousands of people congregate at the temple. In front of the stone idol is a large ant-hill, on which two copper idols are placed, and a brass vessel is placed at the base of the hill, to receive the various offerings.
At a wedding among the nomad Lambadis, the bride and bridegroom pour milk into an ant-hill, and offer cocoanuts, milk, etc., to the snake which lives therein. During the marriage ceremonies of the Dandasis (village watchmen in Ganjam), a fowl is sacrificed at an ant-hill. At a Bedar (Canarese cultivator) wedding, the earth from an ant-hill is spread near five water-pots, and on it are scattered some paddy (unhusked rice) and dhal (Cajanus indicus) seeds. The spot is visited later on, and the seeds should have sprouted.