The Tigrex is a Flying Wyvern known for its highly aggressive nature. The Tigrex lives in the desert and migrates to the Snowy Mountains to feast on Popos, which seems to be its preferred food. They are visibly recognizable by the orangish-yellow skin with blue stripes. Tigrex is the flagship monster of Monster Hunter Freedom 2.
As pseudowyverns, their wings have evolved into forelegs, which makes them very fast, but they only fly when moving to another zone. When coming from a high area, they drop straight down, rather than slowly hovering down like most Wyverns. When they don't see the hunter, however, they may slowly hover down.
In Monster Hunter Frontier, Season 9.0, Tigrex is considerably improved. It now has slightly enlarged horns and is missing one eye; it also has several new attacks, including: a tail-brush, where it wipes its tail in a 180 degree arc behind itself; a vastly improved roar, which covers a far greater area; a frenzied series of agile leaps; a double 360 degree body spin; and finally a triple forward bite.
Monster Hunter Freedom Unite
A flying wyvern that maintains its primitive origins. Prone to violence, it possesses incredible ferocity thanks to its four limbs, claws, and jaw. Inhabits a wide area, it has even been spotted hunting Popo in the mountains.
The Tigrex is known for having improved versions of normal wyvern attacks: it lunges forward to perform a double bite, frequently charges at the player (it can turn 180 degrees to make another pass at the player), executes its tail whip in a 360-degree motion, and can send the player rolling with its roar.
When the Tigrex has been flashed by a hunter it may stay in a spot for a minute but it'll eventually do its special 360. If a blademaster this can be real tricky to try and get out of.
"Ledging" is possible with the Tigrex: when it charges, stand in front of a wall and move away with precise timing and it will bite into the wall, becoming stuck and effectively allowing players to land a few free hits allowing time to cut off tail, as well as dropping Wyvern Tears or Wyvern Sobs (HR6 and above Tigrex).
It is possible to break both front claws, wound the head once (horns/eye) and cut the tail off for more rewards.
Wounding the head will give a chance to obtain Tigrex Skull Shells in the rewards.
While it is in rage mode it is prone to doing its 'Leap Forward' attack. If it performs this attack two times in a row he will often stop for a few seconds and taunt, giving hunters an opening for a full charged attack. When in non-rage mode, it may leap a third time. In G-rank it has been observed doing this while in rage mode.
When weak, the Tigrex will retreat to Area 3 of the Snowy Mountains or Area 9 of the Desert to rest.
In the Desert, Cephalos will occasionally attack Tigrex, in the same way Velociprey sometimes attack Rathian instead of the hunter.
When in rage mode it's eyes will turn red and veins will show up on it's arms, that glow red when blood flows through it's veins.
Tigrex is one of very few monsters that a 'Poisoned/Drugged/Tainted Meat' will work on in Monster Hunter Freedom Unite. After roughly 10-15 minutes of fighting, Tigrex will become hungry enough to cease fighting with the Hunter and consume any 'Meat' item placed in the Area.
In MHF2, clearing the Elder Tigrex Urgent will unlock the video Proof of A Hero.
In MHP3rd, Tigrex's boulder toss will inflict Iceblight if fought in the Tundra and Waterblight if the boulder toss is performed in the secluded and watery areas of the Sandy Plains.
Tigrex's new advancing spin attack in MHP3rd can be easily avoided by standing under its left arm as it advances and rolling away afterwards.
In MHP3rd, if the Tigrex is low on Stamina, every time it attempts to charge it will try to do a U-turn, lose its footing and trip, giving hunters a brief period to attack it freely. Its speed also decreases significantly.
Tigrex will eat Popo (if in the Tundra) or Aptonoth (if in the Sandy Plains) to recover Stamina. To kill them it will perform a double lunging bite.
Unlike previous appearances, in MHP3rd it does not need 2 flinches for the tail to be cut off.
In MHP3rd, Tigrex's arms are enlarged. It will sometimes charge one time, roar and step back to recover from charging and to stop giving hunters free hits.
Tigrex also appears in Monster Hunter Diary: Poka Poka Felyne Village.
When entering Rage Mode, it leaps a distance backward then performs the powerful roar.
When flinching it goes 2 steps backward and shakes its head. It is also performed by Nargacuga when flinched.
Tigrex also has a new, blood coloured rare subpecies that inhabits the Tower.
HC Tigrex is an older dominant male with longer horn/ears, blue tinted wings and roaring power stronger than the Tigrex Subspecies, though it cannot hold a roar as long. It is known for fast unexpected movement, roars focused into an invisible sonic beam easy to spot from sand or snow being blown, an attack were it jumps left-smashes with its foot to the right then jumps ahead to the right and turns then runs back to face its target, double spin attacks like its subspecies and roars so loud the ground cracks beneath it and the air stills as a shock wave reaching beyond its body range.
Monster Hunter 4
A photo found here shows a Tigrex infected by the "Feral Wyvern Virus", which was said to be the status affect of Goa Magara.
Tigrex's Battle theme is changed in Monster Hunter 4.
When defeated, the Tigrex infected with the Feral Wyvern Virus seems to faint, then reawakens with a darker coloration and triggers the new status effect from Goa Magara on all of its attacks, by the looks of it. Other monsters might appear a little differently due to the Virus (Kyoryuka mode) as well. Here's the link