NPS Photo / L. Law 
NPS Photo / L. Law The Bears of Brooks RiverBrooks River is one of many rivers in Katmai. The Brooks is part of the larger Naknek Watershed, meaning that as water flows in the Brooks River, it will eventually make its way to Bristol Bay via the Naknek River.The Brooks River is an essential salmon spawning stream. Salmon pass through this river to other tributaries further upstream, and salmon spawn in this river. Almost all rivers in Katmai are salmon streams, but what makes the Brooks unique is the 6ft high waterfall at the river’s halfway point. This natural dam forces the salmon to school up under the falls before making their leap up and over the falls to their spawning ground. For salmon, this is a helpful resting spot to reserve energy before their push upriver. For the bears however, there is opportunity for feasting on the thousands of fish that come through the Brooks each year. 
NPS Photo / F. Jimenez Brooks River has been a tourist destination since the 1950s and people have started to recognize the individual bears as they return year after year. An ongoing study started in the early 2000s tracks these bears movement patterns and behaviors and is reliant on information from individual bears. In 2012, explore.org set up live streaming cameras that allow visitors from all over the world to engage with these bears and learn about the individuals and their habits. Bear Monitoring at Brooks River An ongoing study on the Brooks River monitors the bears that return each year and their behaviors. To keep track of individual bears that return to the Brooks River each year, the bear is assigned a 3 digit number spanning from 001-999.
How Bear Monitoring Works The Bear Monitor has 5 different monitoring zones along the Brooks River and spends 2-3 hours in a zone. During these monitoring sessions, she spends time identifying the bears in the area, taking photos of the bears for identification, and collects behavioral data (fishing, sleeping, fighting, playing). There are two seasons when the bear monitor collects this data, June-July and late August-October. After monitoring sessions, the Monitor reviews the data to identify the bears by number and note any new bears. A bear must be seen 3 individual times during 3 different monitoring sessions, in one monitoring season, to be officially recorded in the data. For example: an unidentified bear is seen during two different monitoring sessions in June-July. The same bear is seen during one monitoring session in August-October. This bear does not receive a number. Example 2: an unidentified bear is seen three different times during different monitoring sessions in June-July. This bear receives an identification number
June-July
Adult Males (5+ years old) 20, 27, 28, 83, 88, 89, 99, 138, 151, 164, 230, 307, 344, 358, 383, 503, 509, 664, 675, 722, 736, 758, 801, 807, 903, 907, 912 and 913. Single Adult Females (5+ years old) 101, 128, 129, 131, 133, 148, 193, 225, 354, 384, 428, 505, 609, 632, 662, 710, 717, 759, and 910 Adult Females with Cubs* 17 w/ 1 yearling, 26 w/ 2 yearlings, 132 w/ 3COY, 224 w/ 2 COY, 284 w/ 2 COY, 306 w/ 1 COY, 308 w/ 1 COY, 610 w/ 2 COY, 677 w/ 1 COY, 806 w/ 1 COY & 1 adopted 2 year old cub** , 901 w/ 1 COY, 909 w/ 2 COY. Sub-Adults (2-4 years old)(M indicates a male bear, F indicates a female bear) 606M, 620F, 694M, 706M, 735M, and 753F August-October Adult Males (5+ years old) 32, 89, 138, 151, 164, 217, 230, 274, 307, 344, 474, 602, 696, 738, 820, 879, 903, 907, and 913 Single Adult Females (5+ years old) 101, 131, 204, 225, 261, 428, 609, 632, 908, 909, 910 Adult Females with Cubs* 26 w/ 2 yearling, w/ 132 3 COY, 224 w/ 2 COY, 273 w/ 2 COY, 284 w/ 2 COY, 335 w/ 2 COY, 806 w/ 1 COY 1 2 year old**, 831 w/ 2 COY, 901 w/ 1 COY Sub-Adults (2-4 years old) (M indicates a male bear, F indicates a female bear) 620 F, 606 M, and 694 M * "COY" indicates Cub Of the Year, or a first year cub, a "yearling" is cub in it's second summer with their mother bear ** This 2 year old cub spent 2 summers with it's biological mom, bear 128. After normal separation from her biological mom, she joined the 806 family group. Cubs are the most vulnerable bears and the survival rate of cubs along the Brooks River is between 33%-50%. Some of the Adult Females lost cubs throughout the summer, changing where they are denoted in the list above and the number of cubs noted next to their ID number.
June-July
Adult Males (5+ years old) 20, 27, 28, 32, 83, 88, 89, 99, 138, 151, 164, 230, 307, 344,358, 383, 503, 513, 602, 664, 674, 675, 678, 679, 801, 807, 820, 856, 903, 911 and 913 Single Adult Females (5+ years old) 87, 101, 129, 131, 132, 133, 148, 224, 225, 261, 273, 284, 306, 308, 335, 354, 384, 428, 429, 504, 610, 677, 695, 717, 719, 806, 831, 901, 908, 909 and 910 Adult Females with Cubs* 26 w/ 2 COY, 128 w/ 1 female yearling, 153 w/ 1 female yearling, 505 w/ 1 male 2-year-old , and 803 w/ 2 male 2-year-olds Sub-Adults (2-4 years old): (M indicates a male bear, F indicates a female bear) 507 unidentified sex, 606M, 609F, 661M, 662F, 663M, 682M and 694M August-October Adult Males (5+ years old) 27, 32, 83, 89, 99, 151, 164, 217, 230, 274, 307, 344, 348, 474, 602, 680, 696, 801, 820, 856, 879, 903, 907, 912 and 913 Single Adult Females (5+ years old) 129, 131, 132, 133, 224, 261, 273, 284, 306, 308, 335, 428, 429, 504, 610, 719, 831, 901, 908, 909 and 910 Adult Females with Cubs* 26 w/ 2 COY, 171 w/ 2 COY and 128 1 yearling Sub-Adults (2-4 years old) (M indicates a male bear, F indicates a female bear) 609F, 620F, 632F, 606M, 673M, 682M, and 694M * "COY" indicates Cub Of the Year, or a first year cub, a "yearling" is cub in it's second summer with their mother bear Individual Bears at Brooks RiverLearn More About Katmai's Bears
An Intact EcosystemKatmai's brown bears are just one part of its rich ecosystem filled with many other fascinating species. 
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Last updated: November 3, 2026