On what basis vritra is referred to as a snake/dragon?

Question

On what basis vritra is referred to as a snake/dragon? Is there any proof from the vedas? And if not then what was he?

NOTE:— VEDIC VERSES ARE REQUIRED PROVING

Answer 1

Vedas do mention Vritra as 'Ahi' and also give a hint of how he was shaped but it is the Shatapatha Brahmana that mentions his form to have been like that of a serpent. I am sharing the relevant verses from both texts below.

The Rig Veda Book 1 Hymn 32 is dedicated to Indra and recounts his valour in destroying Ahi which is translated as 'dragon' by Griffith:

इन्द्रस्य नु वीर्याणि पर वोचं यानि चकार परथमानि वज्री | अहन्नहिमन्वपस्ततर्द पर वक्षणा अभिनत पर्वतानाम ||

1 I WILL declare the manly deeds of Indra, the first that he achieved, the Thunder-wielder. He slew the Dragon, then disclosed the waters, and cleft the channels of the mountain torrents.

अहन्नहिं पर्वते शिश्रियाणं तवष्टास्मै वज्रं सवर्यं ततक्ष | वाश्रा इव धेनवः सयन्दमाना अञ्जः समुद्रमव जग्मुरापः ||

2 He slew the Dragon lying on the mountain: his heavenly bolt of thunder Tvaṣṭar fashioned. Like lowing kine in rapid flow descending the waters glided downward to the ocean.

वर्षायमाणो.अव्र्णीत सोमं तरिकद्रुकेष्वपिबत सुतस्य | आसायकं मघवादत्त वज्रमहन्नेनं परथमजामहीनाम ||

3 Impetuous as a bull, he chose the Soma and in three sacred beakers drank the juices. Maghavan grasped the thunder for his weapon, and smote to death this firstborn of the dragons.

यदिन्द्राहन परथमजामहीनामान मायिनाममिनाः परोत मायाः | आत सूर्यं जनयन दयामुषासं तादीत्नाशत्रुं न किला विवित्से ||

4 When, Indra, thou hadst slain the dragon's firstborn, and overcome the charms of the enchanters, Then, giving life to Sun and Dawn and Heaven, thou foundest not one foe to stand against thee.

अहन वर्त्रं वर्त्रतरं वयंसमिन्द्रो वज्रेण महता वधेन | सकन्धांसीव कुलिशेना विव्र्क्णाहिः शयत उपप्र्क पर्थिव्याः ||

5 Indra with his own great and deadly thunder smote into pieces Vṛtra, worst of Vṛtras. As trunks of trees, what time the axe hath felled them, low on the earth so lies the prostrate Dragon.

अयोद्धेव दुर्मद आ हि जुह्वे महावीरं तुविबाधं रजीषम | नातारीदस्य सम्र्तिं वधानां सं रुजानाः पिपिषैन्द्रशत्रुः ||

6 He, like a mad weak warrior, challenged Indra, the great impetuous many-slaying Hero. He, brooking not the clashing of the weapons, crushed—Indra's foe—the shattered forts in falling.

अपादहस्तो अप्र्तन्यदिन्द्रमास्य वज्रमधि सानौ जघान | वर्ष्णो वध्रिः परतिमानं बुभूषन पुरुत्रा वर्त्रो अशयद वयस्तः ||

7 Footless and handless still he challenged Indra, who smote him with his bolt between the shoulders. Emasculate yet claiming manly vigour, thus Vṛtra lay with scattered limbs dissevered.

नदं न भिन्नममुया शयानं मनो रुहाणा अति यन्त्यापः | याश्चिद वर्त्रो महिना पर्यतिष्ठत तासामहिः पत्सुतःशीर्बभूव ||

8 There as he lies like a bank-bursting river, the waters taking courage flow above him. The Dragon lies beneath the feet of torrents which Vṛtra with his greatness had encompassed.

नीचावया अभवद वर्त्रपुत्रेन्द्रो अस्या अव वधर्जभार | उत्तरा सूरधरः पुत्र आसीद दानुः शये सहवत्सा न धेनुः ||

9 Then humbled was the strength of Vṛtra's mother: Indra hath cast his deadly bolt against her. The mother was above, the son was under and like a cow beside her calf lay Danu.

अतिष्ठन्तीनामनिवेशनानां काष्ठानां मध्ये निहितंशरीरम | वर्त्रस्य निण्यं वि चरन्त्यापो दीर्घं तम आशयदिन्द्रशत्रुः ||

10 Rolled in the midst of never-ceasing currents flowing without a rest for ever onward. The waters bear off Vṛtra's nameless body: the foe of Indra sank to during darkness.

We get some indication of the vast size and limbless body of Vritra in this Vedic verse but we find something even more concrete in the Shatapatha Brahmana 1.6.3:

8. Tvashtri was furious, and exclaimed, 'Has he indeed consumed my Soma uninvited?' However, he himself desecrated the sacrifice, for what pure (Soma) there was left in the tub he let flow (into the fire), saying, 'Grow thou, having Indra for thy foe!' The moment it reached the fire, it developed, or, as some say, it so developed whilst on its way (to the fire). It became possessed of Agni and Soma, of all sciences, all glory, all nourishment, all prosperity.

9. And since it so developed whilst rolling onwards (vrit), it became Vritra; and since he sprang forth footless, therefore he was a serpent. Danu and Danâyû received him like mother and father 2, whence they call him Dânava.

Further verses also refer to his huge size which may point towards him becoming a huge dragon:

11. And because he (Tvashtri) said, 'Grow thou!' therefore he (Vritra) grew an arrow's range sideways and an arrow's range forward: he forced back both the western ocean and the eastern one; and in proportion as he extended did he devour the food.

Even the description of his dead body is quite informative about his shape:

16. Now Vritra, on being struck, lay contracted like a leather bottle drained of its contents, like a skin bag with the barley-meal shaken out. Indra rushed at him, meaning to slay him.

From these verses we can understand that Vritra was without limbs and therefore like a serpent, was big enough in size to have pushed the limits of the western and eastern oceans and his body was like that of a leather bottle. It would seem to me these verses are quite indicative of him being at least a gigantic serpent if not a dragon.

Answer 2

vrtra's name "ahi" is from proto-indo-european - its cognates are "echidna" (greek) and "anguis"(Latin) meaning snake/dragon and is probably more ancient than "vrtra" = "the enveloper". The story of the killing of a monstrous snake/dragon by a national hero (in this case, Indra) in ancient times is present in many cultures.

Answer 3

Vritra is called "ahi" or snake like in vedas, killed by Indra through a thunderbolt, piercing his "long" stomach.

"In the early Vedic religion, Vritra (Sanskrit: वृत्र, vṛtra, lit. 'enveloper') is a serpent or dragon, the personification of drought and adversary of Indra. In Hinduism, Vritra is identified as an Asura. Vritra was also known in the Vedas as Ahi (Sanskrit: अहि ahi, lit. 'snake'). He appears as a dragon blocking the course of the rivers and is heroically slain by Indra.[1]"

It's surprising to note that all cultures around the world (even the east asian and mid eastern ones)have some sort of story of a dragon being killed by a thundergod or a hero. Hinduism maintains that everyone in satyuga followed one religion and that time world was ruled by the main 33 gods of celestial abode lead by Indra. It could very well be that the same vedic Indra story everywhere turned into corrupted versions of folklore through oral culture.