Jay Dee "B.J." Penn (born December 13, 1978) is an American professional mixed martial artist and Brazilian Jiu-Jitsu practitioner.
 Penn debuted and competed in the Ultimate Fighting Championship (UFC), and later in K-1.
 Prior to fighting for the UFC, he became the first American Gold medalist of the World Jiu-Jitsu Championship.
 In mixed martial arts, Penn has competed in the Featherweight, Lightweight, Welterweight, and Middleweight divisions.
 As a former UFC Lightweight Champion and UFC Welterweight Champion, he is one of only three fighters in UFC history to win titles in multiple weight classes.
 Penn was also a Co-champion in the UFC 41 Lightweight Tournament, due to an eventual draw opposite Caol Uno in the tournament finale.
 Through his tenures as champion, Penn unofficially unified the UFC Lightweight Championship (against Sean Sherk) and broke the all-time lightweight title defense record.
 Penn was inducted into the UFC Hall of Fame, as the inaugural inductee in the Modern-Era Wing by career-long rival Matt Hughes, during "International Fight Week" in July 2015.
Conor Anthony McGregor (Irish: "Conchúr Antóin Mac Gréagóir" ; born 14 July 1988) is an Irish professional mixed martial artist and professional boxer who is currently signed to the Ultimate Fighting Championship (UFC).
 He is the reigning UFC Lightweight Champion, and former UFC Featherweight Champion.
 During his mixed martial arts (MMA) career, McGregor has competed as a featherweight, lightweight, and welterweight.
 As of 2017, McGregor is ranked 2nd on UFC's pound for pound rankings.
Timothy A. Boetsch ( ; born January 28, 1981) is an American professional mixed martial artist currently fighting in the Middleweight division of the Ultimate Fighting Championship.
 In addition to the UFC, Boetsch has formerly competed as an alternate for the New York Pitbulls in the International Fight League and King of the Cage.
 He holds victories over former UFC Champion Johny Hendricks and former bellator middleweight champion Hector Lombard.
 As of July 21, 2017, he is ranked #13 in official UFC Middleweight rankings.
Saul Almeida (born June 4, 1989) is a Brazilian-American professional mixed martial artist currently competing in the featherweight division for the World Series of Fighting.
 A professional mixed martial artist since 2008, Almeida has also formerly competed for Bellator.
Lee Hasdell (born 13 December 1966) is a British martial artist, promoter and former professional kickboxer and mixed martial artist.
 Hasdell is considered by many as a true pioneer of UK mixed martial arts, as he was the main driving force and innovator in the 1990s.
 Hasdell promoted the first professional Mixed martial arts events in the United Kingdom and has helped develop many of the standards within the British MMA scene of today.
Mariusz Ryszard Linke (born July 31, 1969) is a Polish professional mixed martial artist and grappler who is most notable for being the first Polish born black belt in Brazilian jiu-jitsu, the highest ranking active Polish judoka and BJJ practitioner in both mixed martial arts and grappling, and one of the most decorated grapplers in Poland, he is also the first Polish grappler to travel to Brazil and receive training under a Gracie trained Brazilian jiu-jitsu black belt.
 Linke has notably competed in the European Championship, NAGA, Grapplers Quest, ADCC and the Pan American Games.
 Linke is currently in talks with top Polish promotion Konfrontacja Sztuk Walki to negotiate a 2 fight contract to close out his mixed martial arts career by the end of 2015, Linke has stated despite retiring from fighting he will still continue his grappling career and is rumored to be in the 2014 ADCC Polish Trials to enter the 2015 ADCC World Championship.
Akihiko Adachi (安達 明彦 , Adachi Akihiko ) is a Japanese light heavyweight mixed martial artist.
 Adachi was born in Sapporo, Hokkaido, Japan.
 He fought as a professional mixed martial artist from Paraesta Matsudo in Matsudo, Chiba Prefecture beginning in 2000.
 Adachi was the top amateur Shooto light heavyweight in 2002, and was named the Shooto cruiserweight rookie of the year in 2003.
 Adachi's last bout was in 2006 and he formally retired from mixed martial arts in 2008.
Matt Hume (born July 14, 1966) is an American mixed martial artist.
 He is the founder and head trainer at AMC Pankration in Kirkland, WA, which is home to UFC flyweight champion Demetrious Johnson, ONE bantamweight champion Bibiano Fernandes and he has trained numerous world class fighters including Josh Barnett, Tim Boetsch Bob Sapp, Chris Leben, Hayato Sakurai, Akira Shoji, Matt Brown, Rich Franklin, Mario Miranda and Caros Fodor.
Patrick "Pat" Healy (born July 20, 1983) is an American professional mixed martial artist currently competing in the Lightweight division of Titan FC.
 A professional competitor since 2001, Healy has also formerly competed for the UFC, Strikeforce, the WEC, the IFL, the MFC, King of the Cage, ACB and Shark Fights.
 His twin brother, Ryan, is also a professional mixed martial artist.
Dom O'Grady (September 13, 1981 – December 22, 2015) was an American professional mixed martial artist who competed in the Lightweight division.
 He was the former King of the Cage Welterweight and Lightweight Champion.
 He also competed for the Bellator Fighting Championships and Pancrase in Japan.
 In addition to mixed martial arts, O'Grady was 2–0 as a professional kickboxer.

Question: When was the American professional mixed martial artist born who is ranked #13 as of July 21, 2017 and also a trainee of Matt Hume?
Answer: January 28, 1981