[ Last updated April 2, 2006 ]

A methuselah is any 'small' pattern which takes a 'long time' to 'finish'.
I won't try to define "small" or "finish" here, but within this web page
"long time" means at least 15000 generations.  (Note that we can't use
just the initial population to define "small", since a glider aimed at a
distant blinker can take as long as we want to finish, but has only 8 cells.)

The first known pattern which runs for such a long time was 'rabbits',
found by Andrew Trevorrow in 1986:

#C Rabbits.  Runs for 17331 gens.  Initial pop = 9.  Final pop = 1744.
#C Gens 4760-5165 include a rather rare 16-bit still-life called a "scorpion".
x = 7, y = 3
o3b3o$3o2bo$bo!

Five 1-generation, 9-cell predecessors of rabbits were found later.  The
first of these, found independently by Trevorrow and Robert Wainwright,
is called "bunnies":

#C Bunnies and four other 1-gen, 9-cell predecessors of rabbits.
#C Each runs for 17332 gens.
x = 60, y = 5
o5bo12bo39bo$2bo3bo6bobo3bo6bo3bob2o9bob2o9bobo$2bo2bobo7bo2bobo6b2o3b
o6b3o3bo6b3o3bo$bobo12bo12bo2bo8bo3bo8bo2bo$14bo!

Trevorrow also found a 2-generation, 9-cell predecessor in October 1995:

#C 2-gen, 9-cell predecessor of rabbits.  Runs for 17333 gens.
x = 8, y = 3
2bo4bo$2o$b2ob3o!

In 1997 Paul Callahan did a survey of 9-cell patterns and found some
relatives of rabbits which last about 80 gens longer:

#C Runs for 17410 gens.  Initial pop = 9.  Final pop = 1744.
x = 8, y = 7
bo$2o5bo$6bo$6bo$5bo$4bo$4bo!

#C Runs for 17409 gens.  Initial pop = 9.  Final pop = 1744.
x = 8, y = 7
bo$2o5bo$6bo$6bo$5bo$4bo$3bo!

In 2001 I found two others that last for 17409 gens.  (Paul Callahan probably
found these earlier, but I don't think he mentioned them.)

#C Two 9-cell relatives of rabbits.  Each runs for 17409 gens.
x = 36, y = 7
bo27bo$2o4bo21b2o5bo$7bo27bo$6bo27bo$4b2o26b2o2$3bo27bo!

I found some slightly larger rabbits relatives in 2001 and 2002:

#C Rabbits relative.
#C Runs for 17421 gens.  Initial pop = 11.  Final pop = 1744.
x = 6, y = 5
3b3o$obo$o4bo$bob2o$o!

#C Rabbits relative.
#C Runs for 17429 gens.  Initial pop = 11.  Final pop = 1744.
x = 5, y = 7
o$o$2bo$bo2bo$bo2bo$o3bo$2o!

#C Rabbits relative made of common objects.
#C Runs for 17434 gens.  Initial pop = 12.  Final pop = 1744.
x = 15, y = 7
3o$13b2o$12b2o3$3b3o$3bo2bo!

#C Rabbits relative that fits in 2 rows.
#C Runs for 17410 gens.  Initial pop = 12.  Final pop = 1744.
x = 9, y = 2
b3o2b3o$o2b5o!

Tomas G. Rokicki found some others:

#C Rabbits relative.
#C Runs for 17423 gens.  Initial pop = 10.  Final pop = 1749.
#C May be the longest-lived 10-cell pattern within a 10x10 square.
#C Found by Tomas G. Rokicki, some time before Feb 21, 2005.
x = 6, y = 6
bo$2obo$4b2o$o2bo$o$o!

#C Rabbits relative.
#C Runs for 17465 gens.  Initial pop = 11.  Final pop = 1749.
#C May be the longest-lived 11-cell pattern within a 11x11 square.
#C Found by Tomas G. Rokicki, some time before Feb 21, 2005.
x = 6, y = 4
ob3o$o4bo$obobo$bo2bo!

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Turning to patterns that aren't relatives of rabbits, Paul Callahan found
this one in 1997:

#C Runs for 21035 gens.  Initial pop = 32.  Final pop = 2570.
#C Final census includes a 'big S' (a 14-cell still-life), which forms
#C in gen 20040 from a collision between a pi-heptomino and a boat.
#C The pattern also produces 2 temporary pulsars, one in gens 10105 to 10153,
#C the other in gens 10338 to 10735.
#C Found by Paul Callahan, 1997.
x = 8, y = 8
obo3b2o$3ob2o$obobobo$3bo3bo$o2bob2o$obo4bo$3o2b3o$2o3bobo!

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In Feb. 2002 I found one that lasts longer than that:

#C Runs for 21729 gens.  Initial pop = 46.  Final pop = 2913.
#C Found by Dean Hickerson, 2/24/2002
x = 13, y = 12
2bo$2bo5bob2o$2bobo5bo$2b4o5bo$10b2o$3bo5b3o$b2o2bobo3b2o$8b2ob2o$2b2o
bo6bo$bobo3bo3bo$o5b2o2b2o$5b2o2b2o!

Here's a relative whose population is only 23; it finishes 32 gens sooner:

#C Runs for 21697 gens.  Initial pop = 23.  Final pop = 2913.
x = 10, y = 18
o$2o$b2o3bo$6b2o$7bo5$3bob2o$2b2o$4bo2b2o$9bo$7b2o2$5bo$5bo$5bo!

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In July 2002 I found this one that lasts even longer, and starts out
smaller:

#C Blom.  Runs for 23314 gens.  Initial pop = 13.  Final pop = 2740.
#C Found by Dean Hickerson, 7/7/2002
x = 12, y = 5
o10bo$b4o6bo$2b2o7bo$10bo$8bobo!

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In Feb 2005, Tomas G. Rokicki found this pattern:

#C Runs for 23334 gens.  Initial pop = 12.  Final pops = 2898/2895
#C May be the longest-lived 12-cell pattern within a 12x12 square.
#C Emits a LWSS in gen 13811.
#C Found by Tomas G. Rokicki, some time before Feb 21, 2005.
x = 8, y = 5
4b3o$3bo$o5bo$b2o2bobo$bobo!

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In May 2004, Andrew Okrasinski set a new record:

#C Justyna.
#C Runs for 26458 gens.
#C Initial pop = 20. Final pop = 3548/3546.
#C Gliders = 43.
#C Found by Andrew Okrasinski, 5/30/2004
x = 22, y = 17
17bo$16bo2bo$17b3o$17bo2bo2$2o16bo$bo16bo$18bo8$19b3o$11b3o!

In August 2004 he found this one:

#C Iwona.
#C Runs for 28786 gens.
#C Initial pop = 19. Final pop = 3091.
#C Gliders = 47.
#C Found by Andrew Okrasinski, 8/20/2004
x = 20, y = 21
14b3o6$2bo$3b2o$3bo14bo$18bo$18bo$19bo$18b2o$7b2o$8bo5$2o$bo!

In July 2005 he found this:

#C Lidka.
#C Runs for 29053 gens.
#C Initial pop = 15. Final pop = 1625/1623.
#C Gliders = 28.
#C Found by Andrzej Okrasinski, 7/13/2005
x = 9, y = 15
bo$obo$bo8$6b3o$5bo2bo$4bo3bo$4bo$4b3o!

David Bell pointed out that it could be backed up 2 generations, making it
2 cells smaller:

#C 2-gen predecessor of Lidka
#C Runs for 29055 gens.
#C Initial pop = 13. Final pop = 1625/1623.
#C Gliders = 28.
#C Found by David Bell, 7/15/2005
x = 9, y = 15
bo$obo$bo8$8bo$6bobo$5boobo$$4b3o!

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I don't know of any others that last more than 20000 gens, but here are
some that last more than 15000 gens, listed in decreasing order of longevity:

#C Runs for 19258 gens.  Initial pop = 17.  Final pop = 2437.
#C Found 4/8/2002
x = 11, y = 14
5b3o2$9bo$3b2o3bobo$2b2o4b2o8$3o$o2bo!

#C Runs for 19248 gens.  Initial pop = 18.  Final pop = 3209.
x = 12, y = 11
o2b2o$2obo$b2o$2bo4$2b2o$3b2o$4b2o4b2o$10bo!

#C Runs for 19178 gens.  Initial pop = 29.  Final pops = 1654/1652.
x = 21, y = 8
6b2o3bo$2o4bo$o5b2ob2o9bo$3obo3b3o9bo$2bo4bo12bo$2b2o$2bob2o$3bo!

#C Runs for 19084 gens.  Initial pop = 14.  Final pop = 2501
#C Found by Tomas G. Rokicki, some time before 2/17/2005
#C Produces a temporary integral sign, from gens 14584 to 15255.
x = 8, y = 4
3o3bo$bobob2o$b2o4bo$b3o!

#C Runs for 18692 gens.  Initial pop = 41.  Final pop = 1919.
x = 20, y = 23
10bo$9bobo5bo$9b2o6b2o3$bo$3o16bo$7b2o6bo2bo$8bo6b3o8$5b2o3b3o$4b2o4bo
2bo$4bo5bo3bo$14bo$10bo3bo$10bo2bo$10b3o!

#C Runs for 18474 gens. Initial pop = 35.  Final pop = 2104.
x = 27, y = 13
17b3o$17bo2b2o3b2o$18bo7bo$17bo6bo$b2obo11bo7bo$bo2b2o5bo4bo8bo$2o10bo
2bo$3bo9bo$3bo10bobo3$3b2o$4bo!

#C Runs for 18411 gens.  Initial pop = 20.  Final pops = 1818/1820.
#C Found 3/30/2002
x = 15, y = 6
6b3o$o8bo$o4bo4bo$o3b3o2bo$2bo6b2ob3o$2bo!

#C Runs for 17475 gens. Initial pop = 23.  Final pop = 2598.
#C Emits a LWSS at gen 15407.
x = 15, y = 12
6b2o$4bob3obo$10bo$o$2o$o12bo$12bobo$11bobo$11b2o$7bo$7b2o$8bo!

#C Runs for 17309 gens.  Initial pop = 30.  Final pop = 2026.
x = 14, y = 23
2o$o3$12b2o$13bo8$11bo$11bo$10bo2$10b3o$3b2o5b2o$3bobo4bob2o$5bo6b2o$
4b2o5b3o$12bo!

#C Runs for 17301 gens.  Initial pop = 16.  Final pop = 3537.
#C This runs about as long as rabbits, but produces more than twice as
#C much debris.
x = 12, y = 11
9bo$8b2o$9b2o$9bo$9bo2$b2o$2o$9bo$9b3o$10bo!

#C Runs for 17184 gens.  Initial pop = 22.  Final pop = 2327.
x = 11, y = 12
9bo$8b2o$3o5bo$2bo$3bo$bo$7b2o$7bo2bo$6b2o2bo$5bo4bo$5bo3bo$5bo!

#C Runs for 16677 gens.  Initial pop = 13.  Final pops = 2603/2600.
#C Produces a LWSS about gen 10600.
x = 7, y = 7
o$o$o3bo$4b2o$5b2o$5b2o$2b3o!

#C Runs for 16473 gens.  Initial pop = 18.  Final pop = 2016.
#C Makes a temporary pair of tables from gens 2439 to 5469.
x = 15, y = 7
bobo7bo$bo8b3o$2bo$2o$b2o10b2o$9b2o3bo$10bo!

#C Runs for 16422 gens.  Initial pop = 12.  Final pops = 1795/1793.
x = 6, y = 6
b3o$o2bo$4b2o$5bo$3b3o$4bo!

#C Runs for 16298 gens.  Initial pop = 24.  Final pop = 2682.
x = 11, y = 12
3bo$b4o$b4o4bo$9b2o2$2o$bo3$2b2o5bo$b2o5bobo$8b2o!

#C Runs for 16193 gens.  Initial pop = 18.  Final pop = 1943.
x = 23, y = 13
b2o$2o2$20b3o3$20bo$20b2o3$21bo$10b2o8bobo$10bo9b2o!

#C Runs for 16171 gens.  Initial pop = 14.  Final pop = 1777.
x = 15, y = 11
4bo$3b2o$3bo3$13b2o$14bo$12b2o$o11bo$b2o$bo!

#C Runs for 16618 gens.  Initial pop = 21.  Final pop = 1705.
x = 18, y = 19
3b2o$2bo$2bo$3bo$bo3bo$3obo$bo2bo9$15b2o$16b2o$14bobo$14b2o!

#C Runs for 16123 gens. Initial pop = 20.  Final pop = 1640.
x = 9, y = 9
3b3o$b3o2$o3bo$bob2o$2b3o$4bo3bo$7bo$4b3o!

#C Runs for 16019 gens. Initial pop = 26.  Final pop = 2052.
#C Final census includes a shillelagh.
x = 17, y = 16
12b2o$12b2obo$11bo2bo$16bo$16bo$6bo8b2o$5bo$5b3o$2o$bo2$15b2o$15bo$11b
o$10b2o$10bo!

#C Runs for 15846 gens.  Initial pop = 26.  Final pop = 1793.
#C Final census includes a paper clip.  Another exists during gens 1140-1614.
x = 16, y = 25
6b2o$6bobo$7bobo$8bo3$o$o$o10b2o2$11bo2bo$13b3o$11bobo2$6b2o$7bo7$4bo$
3b2o$3bo!

#C Runs for 15105 gens. Initial pop = 21.  Final pop = 1809.
x = 10, y = 7
bo2bo$2b2o2bo$2o4bo2bo$o2bo3b3o$o4b2o$5b2o$2o!