In Warframe, you will need Medjay Predasite Tags to rank with the Entrati union. To obtain them, you will need to engage in animal conservation on the Cambion Drift on Deimos.
What do you need
You will need very specific objects to get a chance to catch a medjay predium. First of all, you will need a Tranq rifle that you can buy from its in the necralisk if you do not already have 1. This will cost you 500 standing. You will also have to buy an ECHO predium lure from its for 1000 standing, and finally you will need a pédasite pheromone gland. These single-use objects cost 150 standing points and increase the scarcity of the predasitation that appears when you follow them.
How to capture a medjay predium
Head to the Cambion Drift and take out your TRANQ rifle. Switch to the ECHO predium lure for only these sites appear on the map, and then go to one of them. Once there, find the animal’s poop and interact with him, then follow the trail. The predominant trails are quite easy to follow, just do not get into the toxic shit.
When you arrive at the nest, use the Predasite Praémone gland before using the ECHO lure. This will increase the chances of spawning a predian medjay. Use the echo lure, then repeat the predium call and return to the TRANQ rifle. When the animal comes out, hit twice with the Tranq rifle. If you are lucky, a Medjay will appear, otherwise you will have to rinse and repeat until you have one.
Remember that invisibility warframes facilitate the capture of animals, because the animal will not know that you are there.