Blood

Blood is used to transport nutrients through the body of a multicellular organism. In the case of humans, it uses a compound called haemoglobin and hormones to transport Oxygen to the cells. Because of cellular respiration, every single cell in the human body needs oxygen, so blood must deliver oxygen to every cell in the body. This is most likely true to most of the other Covenant races, with the exception of the Unggoy, though their blood may be delivering a different compound to the body, resulting in its difference in color to human blood.
==In the Halo Series==
When shot without the protection of an energy shield, the target will "bleed." In some races, the blood will visibly come out of the target, and leave a stain on the ground. The viscosity and color of the blood varies by race.
===Covenant===
*Sangheili - Dark Blue/Purple (Halo: Combat Evolved),:File:Bloody.jpg (Corpse was meleed multiple times.) Purple (Halo 2 and Halo 3).
*Jiralhanae - Dark Navy Blue/Black (Halo 2), Purplish Red, Thick (Halo 3).
*Mgalekgolo - Bright Orange.
*San'Shyuum - Red.
*Kig-Yar - Purple, thick.Halo: The Fall of Reach, page 126
*Unggoy - Light Blue, Teal, Very Thick.:File:GruntBlood.jpg (Halo: Combat Evolved), (Halo 2), and (Halo 3) electric blue (Halo: Reach).
*Yanme'e -  Beige, green tint, with dark turquoise green splotching.
*Huragok - Reddish pink.Halo Graphic Novel, page 18 Luminescent Blue (Halo 3: ODST), (Halo: Reach).
===Forerunner===
*Forerunners - Purple (at least in Lifeworkers).Halo: Silentium
*Promethean Knight - Bright Orange.
*Promethean Crawler - Bright Orange.
===Others===
As in reality, Humans will bleed red blood when shot. Forerunner artifacts, such as the Menachite Forerunner Complex, may at times be manipulated by human blood.Halo: First Strike, page 141: Fred felt a hot pain in the tip of his finger. He drew his bare hand away and a tiny track of blood smeared the rock. The glittering symbols on the wall took on a greasy cast(..) The Flood will always bleed a pasty, brownish-green color, and the explosion of a Carrier Form or an Infection Form will leave a brown stain on the ground. In gameplay, however, Infection forms do not "bleed," but rather explode into bits of flesh.
==Trivia==
*Sometimes on Halo: Combat Evolved bullet holes with blood and/or blood splatters will be visible at certain angles though nothing was there or nothing was shot or hurt(Bullet Hole Glitch).
*In Halo: The Flood, the word ichor was used instead of the word blood. Ichor was the golden blood of the Greek Gods of Olympus.
*The blood and the amount of blood of Covenant foes changes during the course of the three Halo games. For example, Unggoy, Sangheili, Mgalekgolo and Kig-Yar bled profoundly when meleed in Halo: Combat Evolved, and yet, in Halo 2, the player must shoot the corpse in order for it to bleed. In Halo 3, the amount of blood is lessened dramatically, but is given in greater detail. Unggoy blood also seems more viscous, as opposed to slightly watery looking in the earlier games.
*In Halo 3, when a Jiralhanae is shot and blood is spilled, there seems to be odd luminous chunks in the blood. You can see this in human blood as well.
*Sometimes in Halo: Combat Evolved on the Xbox, the game will lag if too many blood decals are being rendered.
*"Blood" is a Sangheili curse word.Halo: The Cole Protocol, page 140
*The Jiralhanae are the only race to have significantly different colored blood from one game to another, although in some Halo Legends episodes, other species also have different blood color than the games.
*In Halo: Combat Evolved, when you melee Covenant species (most effectively on Kig-Yar), an unlimited amount of blood will come out.
* In the Halo: CE level "The Silent Cartographer" when you melee a dead Hunter, he will squirt out Flood blood.
*In Halo: Reach, blood is less "messy," but much more rich and detailed. It will only appear on the environment when one player is signed in.
*Unggoy Blood has been described to actually have a stench; close to something like rotten eggs, possibly due to them breathing methane or their diet.
*Sangheili blood has a smell of fresh tar.
*Mgalekgolo blood has a smell of burnt rubber.
==Gallery==
File:1215574434 Brute3.jpg|A Jiralhanae's blood after being killed by a grenade.
File:Jackalblood.jpeg|A Kig-Yar's blood stain, Halo: Combat Evolved era.
File:1215645880 Jackal Blood.jpg|A Kig-Yar's blood stain, Halo 3 era.
File:1215578204 Hunter.jpg|A Hunter's blood after it was killed by an explosive.
File:Hunter_blood.jpg|Mgalekgolo Blood. Note the luminous properties
File:1215495677 43652110-Full.jpg|A Drone's blood stain.
File:1220721402 Dead grunt.jpg|A Unggoy's blood stain.
File:Bloody.jpg|This image shows that in Halo: CE, a Sangheili's blood is actually a dark blue.
File:Huragok blood.jpg|Huragok blood.
==Sources==
Category:Biology