Haveyoueverwonderedhow
muchaBisonweighs?
(Activitiesusingprediction,hypothesisandoneyearofweightdata)
BisonroamoverthetallgrassprairieattheKonzaPrairieBiologicalStation.Outhereon
theprairiethebisoncalvesareusuallyborninthespring(AprilandMay)andarefed
theirmother’smilkuntiltheystarteatinggrassataround6monthsofage.
ThebisonatKonzaPrairiehavealargeopenpastureofapproximately2,500acreson
whichtheyroamfreely.Thesebisonfeedonthegrassandotherprairieplantsandare
notfeedextragrassorhay–noteveninthewinter.
EveryyearattheendofOctoberthebisonatKonzaPrairieareroundedupandweighed
onaspecialscale.Theweightofthebisoncangivescientistssomeinformation.
1. Duringwhatmonthoftheyeardomostbisoncalvesstarttoeatgrassforthe
firsttime?
2. Howmuchtimedonewbisoncalveshavetoeatgrassbeforetheyareweighed
inOctober?
3. Whodoyouthinkwouldweighmore,abisoncow(adultfemale)orabisonbull
(adultmale)?
4. DoyouthinkallofthebisoncalvesweighthesameinOctober?
5. Findtheweightforthelightestcalf.Nowfindtheweightfortheheaviestcalf.
Whatisthedifferencebetweentheirweights?
6. Whydoyouthinkthereissomuchvariationinthecalfweights?Thinkaboutthe
kindsofthingsthatcouldmakeacalfweighlessweight.
Bisonweightdata-2010:
Weight Eartagcolor
andnumber
Femalecalves:
162pounds 228pounds 242pounds 248pounds 266pounds 278pounds 296pounds 330pounds Orange–009
Orange-040
Orange–049
Orange-010
Orange–027
Orange-062
Orange-059
Orange-044
Malecalves:
180pounds
240pounds
252pounds
274pounds
298pounds
350pounds
360pounds
378pounds
Orange-017
Orange–038
Orange–014
Orange-007
Orange-057
Orange–045
Orange-018
Orange-032
Cows: (adultfemales)
Bulls: (adultmales) 420pounds 550pounds 688pounds 804pounds 852pounds 898pounds 994pounds 1,062pounds Yellow-918
Yellow-941 Yellow–846
Yellow-834
Yellow–355
Yellow-411
Yellow-328
Yellow-324 1,266pounds 1,338pounds 1,342pounds 1,408pounds 1,586pounds 1,602pounds 1,612pounds 1,616pounds Yellow-721
Yellow–637
Yellow-688
Yellow-642
Yellow-309
Yellow–339
Yellow-331
Yellow-421 Eartagcolors:
• Orangeeartagsarefoundinanimalsthatwerebornbetween2010–2019
• Yelloweartagsarefoundinanimalsthatwerebornbetween2000-2009
• The1stnumberineacheartagcorrespondstotheYEARthebisonwasborn.
E.g.Yellow421wasbornin2004.
Suggestedactivities:
Thebisonoutlinesmaybereusediftheyarelaminated.
Backgroundinfo:bisonbabiesarecalled“calves”ora“calf”,bisonadultfemalesare
called“cows”,andbisonadultmalesarecalled“bulls”.
Bisonweightranges:
Calf 150pounds–380pounds
Cow 400pounds–1,100pounds
Bull 1,200pounds–2,000pounds
1. Makephotocopiesofthebisonoutlines.Writeoneoftheprovidedbison
weightsinthecenterofeach(useeachweightonlyonce).Passthemouttoyour
studentsandaskthemthesequestions:
• Whichbisonweightsdoyouthinkarecalves?
• Whichbisonweightsdoyouthinkarecows?
• Whichbisonweightsdoyouthinkarebulls?
2. Haveyourstudentsstandupandputtheirbisoninorderinalineonthefloor
fromthelowestweight(ontheleftside)uptothehighestweight(ontheright
side).
Thenaskthem:
• Isitsurprisinghowdifferenttheweightsareinaherd?
• Whatisthedifferenceisbetweenthesmallestbisoncalf’sweightandthe
largestbisonbull’sweight?
• Isitsurprisinghowwidelydifferenttheweightscanbeinonespecies?
3. Morechallenging:Havethestudentsrefertotheirbison.Givethemthetableof
bisonweightsandaskthemtofindtheirbisonanddetermine:
• Theirbison’sgender
• Whatistheirbison’seartagnumber
• Theirbison’sage
4. Constructapictographonthewhiteboardandhave8columnsdividedbyage:6
mo.,1,2,3,4,5,6,7yearsofage.Givethestudentstheweightandeartagdata
andhavethemdeterminetheirbison’sage.Havethembringtheirbisonupto
theboardandseewhatageisthemostabundantinthebisonherd.
Femalecalves
162lbs.
228lbs.
lbs.
242lbs.
248lbs.
lbs.
266lbs.
278lbs.
296lbs.
330lbs.
Malecalves
180lbs.
lbs.
240lbs.
lbs.
252lbs.
lbs.
274lbs.
lbs.
298lbs.
lbs.
350lbs.
lbs.
360lbs.
lbs.
378lbs.
lbs.
Cows
420lbs.
lbs.
550lbs.
lbs.
688lbs.
lbs.
804lbs.
lbs.
852lbs.
lbs.
898lbs.
lbs.
994lbs.
lbs.
1,062lbs.
lbs.
Bulls
1,266lbs.
lbs.
1,338lbs.
lbs.
1,342lbs.
lbs.
1,408lbs.
lbs.
1,586lbs.
lbs.
1,602lbs.
lbs.
1,612lbs.
lbs.
1,616lbs.
lbs.