A Tranq Rifle is a very important piece of equipment in Warframe, and is used for animal capture and conservation. Many players are currently searching for it due to the Heart of Deimos expansion. If you want to progress in the Entrati Syndicate, you need to perform animal captures for Son to get Son Tokens.
Son is the animal capture NPC in the Necralist, and he sells most of the things that you need for animal conservation. For some reason, he does not sell a Tranq Rifle. To get your hands on this piece of equipment, you will need to visit The Business at Fortuna on Venus. He will sell you a Tranq Rifle that you can use for capturing animals for 500 Solaris Standing.
To earn Solaris Standing, visit Eudico near the gates to Orb Vallis in Fortuna. All her bounties will award a different amount of Standing, and doing any of them will net you enough to buy the Tranq Rifle.
It is certainly a little odd that Son doesn’t sell Tranq Rifles himself, but it is not very difficult to get one, and just involves a quick trip to Fortuna to sort it out.
If you want more information on how to capture animals on Deimos, we have a guide that will tell you everything you need to know. We also have a guide on how to perform perfect animal captures, as this can often be a Nightwave challenge that players will need to complete.