Metal Gear Solid 5: Mission 31 Sahelanthropus - Prima Games

Metal Gear Solid 5: Mission 31 Sahelanthropus

by Prima Games Staff

This guide will help you earn an S Rank for the story mission Sahelanthropus in Metal Gear Solid 5: The Phantom Pain, and includes a list of the mandatory and optional objectives available for this mission. Note that it is not necessary to complete all the objectives to earn an S Rank. You just need to accumulate a score of 130,000 or more, and earning the time bonus will greatly increase your chances of getting an S Rank score. Focus on completing the mission quickly in order to earn the time bonus needed to secure an S Rank rating. 


  • Destroy Sahelanthropus (Mandatory).
  • Destroy the head of Sahelanthropus (Optional).
  • Successfully hit the floating  boy with an attack (Optional). 


This mission solely consists of a boss battle against the Sahelanthropus. Before you begin the mission, equip yourself with some strong weapons at the prep screen. We opted to use the grenade launcher and rocket launcher for the added stopping power and high penetration. You may also choose to bring your favorite assault rifle to take down projectiles if necessary. 

The boss battle will commence as soon as you start the mission. Sahelanthropus has a couple weak areas that you should target, including the glowing part of its abdomen as well as some white canisters hanging from his back. Aim for these weak points to inflict more damage per shot. 

A supply drop will automatically be called in when you run out of ammo. Just make sure the Sahelanthropus does not destroy the chopper, or you will have to call in supply drops manually after that.

If the Sahelanthropus whips the ground to surround you with dark rocks, then just stand still and make sure not to touch the rocks, otherwise they will explode and cause you damage. If the Sahelanthropus leaps to a nearby cliff, simply run to the base of the cliff where it is standing to take cover from the incoming laser beam. 

Stay mobile throughout the boss fight, and continue to blast the Sahelanthropus with your rockets as much as you can. Once you have reduced its health meter to just below a quarter, this will trigger Reflex Mode with the Sahelanthropus, and the floating boy will become visible. Quickly switch to an automatic weapon to shoot directly at the floating boy, briefly disabling the machine. You will have a short moment to fire off some rockets at the Sahelanthropus’ exposed head. You can take this opportunity to destroy the head of boss, completing one of the optional objectives.

Continue firing at the Sahelanthropus until you completely deplete its health bar. Afterwards, the mission will conclude with a series of cutscenes. In the interest of time, you should skip the cutscenes to ensure a higher score for an S Rank rating.  However, if this is your first playthrough, then you should watch the cutscenes to take in the full story experience, and come back to earn your S Rank on a second playthrough of the mission. 

Continue to Mission 32: To Know Too Much, or return to the Metal Gear Solid 5 Walkthrough and Guide.

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