I know that sanatana dharma is the oldest religion. But are there any evidences or any mentions of other religions in the vedas? If yes,what were the religions?
Jainism is world's 2nd oldest religion. It is in existence since Satya Yuga. Their first Tirthankar - Rishabhadeva was incarnation of Lord Vishnu.– PinakinFeb 19, 2016 at 14:57
1(SanAtan) Dharma is not Religion. Shaivism & Vaishnavism were 2 of the old religions, which are now combined in Hinduism. Buddhism & Jainism are also religions branched from India. Usually religions have more to do with organized way of worshipping. They often help upholding Dharma due to its usually well defined guidelines.– iammilindFeb 19, 2016 at 15:02
@ChinmaySarupria In Satya Yuga there will be no Religion or cities. People just live in forests and do Tapasya. Satya Yuga is Saatvic and way of life is different from Kali Yuga.– The Destroyer ♦Feb 19, 2016 at 15:38
1@ChinmaySarupria Not just since the Satya Yuga, Jainism has been around since some previous Manvantara. Rishabha was a descendant of the ancient king Priyavarta, who ruled in the Swayambhuva Manvantara.– Keshav Srinivasan ♦Feb 19, 2016 at 16:22
1@SachinBahukhandi * But after the destruction of the 3 cities the bald man came & asked Lord Vishnu-" What shall i do now considering that the purpose of my creation has been served?"The Lord answered that you will have to wait till kali yuga when again you need to resume preaching this false dharma in a desert.According to Bhavisya purana too, the re inacranation of tripurasura is said to create a barabaric religion.in the desert of which you must be quite aware of .:)– RickrossFeb 22, 2016 at 6:10
Rig veda I.110 says about Ṛbhus
When, seeking your enjoyment onward from afar, ye, certain of my kinsmen, wandered on your way, Sons of Sudhanvan, after your long journeying, ye came unto the home of liberal Savitar.
Savitar therefore gave you immortality, because ye came proclaiming him whom naught can hide; And this the drinking-chalice of the Asura, which till that time was one, ye made to be fourfold.
These mantras are talking about existence of different methods/religious rituals in Vedic Era, other than Spirituality.
Here immortality does not indicate a boon to live forever,which in the subsequent literature described as chiranjIvatva, but only permanent BLISS emanated out of SELF REALISATION.
In Ramayana, Sri Hanuman was described as the follower of dakshinAchAra - Vedic way of life.
अञ्जलिं प्राङ्मुखः कृत्वा पवनायात्मयोओनयो | ततो हि ववृधे गन्तुं दक्षिणो दक्षिणां दिश्म् || ५-१-९
Hanuma, follower of dakshinAchAra, turned towards east, saluted his father, the Lord of Wind and increased his body to go towards southern direction.
In this sloka दक्षिणो indicates follower of dakshinAchAra, दक्षिणां दिश्म् indicates in Southern direction.
So there existed vAmAchAra - the way of life that opposed to vedic way of life.
While giving away her ear rings, the queen of king Paushya, she warns Utanka about King of Serpants, Takshaka, who is waiting to steal those ear rings.
'These ear-rings are very much sought after by Takshaka, the King of the serpents. Therefore shouldst thou carry them with the greatest care.'
On the road Utanka perceived coming towards him a naked idle beggar sometimes coming in view and sometimes disappearing. And Utanka put the ear-rings on the ground and went for water. In the meantime the beggar came quickly to the spot and taking up the ear-rings ran away.
Narrating appearance of Takshaka in the form of a naked beggar, might be a pot shot against Jainism, which existed at the time of composition of Mahabharata in Classical Sanskrit.