Ancient Human Footprints in Ciur-Izbuc Cave, Romania

David Webb,1* Marius Robu,2 Oana Moldovan,2 Silviu Constantin,2 Bogdan Tomus,3 and Ionel Neag3

1Department of Anthropology, Kutztown University, Kutztown, PA2“Emil Racovitza” Institute of Speleology, Romanian Academy, Romania3Clubul Speologilor Proteus Hunedoara, Romania

KEY WORDS human footprints; stature estimation; minimum number of individuals;cave occupation

ABSTRACT In 1965, Ciur-Izbuc Cave in the Carpa-thian Mountains of Romania was discovered to containabout 400 ancient human footprints. At that time,researchers interpreted the footprints to be those of aman, woman and child who entered the cave by an open-ing which is now blocked but which was usable in antiq-uity. The age of the prints (�10–15 ka BP) was basedpartly on their association with cave bear (Ursus spe-laeus) footprints and bones, and the belief that cavebears became extinct near the end of the last ice age.Since their discovery, the human and bear evidence andthe cave itself have attracted spelunkers and other tou-rists, with the result that the ancient footprints are indanger of destruction by modern humans. In an effort toconserve the footprints and information about them andto reanalyze them with modern techiques, Ciur-Izbuc

Cave was restudied in summer of 2012. Modern resultsare based on fewer than 25% of the originally describedhuman footprints, the rest having been destroyed. It isimpossible to confirm some of the original conclusions.The footprints do not cluster about three different sizes,and the number of individuals is estimated to be six orseven. Two cases of bears apparently overprintinghumans help establish antiquity, and C-14 dates sug-gest a much greater age than originally thought.Unfortunately, insufficient footprints remain to mea-sure movement variables such as stride length. How-ever, detailed three-dimensional mapping of thefootprints does allow a more precise description ofhuman movements within the cave. Am J Phys Anthro-pol 000:000–000, 2014. VC 2014 Wiley Periodicals, Inc.

Ancient human footprints from the very late Pleisto-cene have been reported at Chauvet Cave in France at33–24.5 ka (Garcia, 2005; Valladas et al., 2005), Willan-dra Lake in Australia at 23–19 ka (Webb et al., 2006a,2006b), and on Jeju Island in Korea at 25–19 ka (Kimet al., 2010). All of these sites have been dated to lessthan 50,000 years ago. In Romania, three late Pleisto-cene footprints have also been found in Vartop Cave, butthese are somewhat older (97–62 ka) and are consideredto have been made by a Neanderthal (Onac et al., 2005).However, in 1965, a group of speleologists and anthro-pologists performed a preliminary study of Ciur-IzbucCave in Romania, including about 400 human footprintsthat were discovered in the upper level. In the process,they marked about 230 prints with small metal flagsplanted in the soft sedimentary floor of the cave (Rusuet al., 1969). Many of the metal flags can still be found,apparently in their original positions, but quite a fewhave been trampled by subsequent human incursion intoCiur-Izbuc Cave, while others are not currently nearany visible imprints.

In 1970, Riscutia and Riscutia, the anthropologists inthe group, published their preliminary analysis of 188footprints that they deemed sufficiently well-preservedto be measured. In their opinion, the prints fell natu-rally into three categories according to size and shape: alarge, a medium-sized and a small individual which theyinterpreted as a man, a woman and a child. Theyreported print length (“Pte–Ap”), ball width (“Mtm–Mtl”), heel width, length of the plantar impression (with-out toes) and the “crucial index” (ball width/printlength), as in Table 1 (in translation).

In addition to marking and measuring each footprint,all prints were photographed and two prints were cast

in plaster. It was the intention of Riscutia and Riscutiato return to Ciur-Izbuc Cave to continue their analysisof the footprints, hopefully producing a map of the caveand prints and measuring gait parameters such as steplength and foot angle (Riscutia and Riscutia, 1970).Unfortunately, they never returned and since that timeall records have been lost, including the original photo-graphs and measurements. Furthermore, the majority ofthe prints are now lost to the destructive effects of tour-ism, and only recently was a gate installed across theentrance to the cave, restricting access to a relativelysmall number of tourists and scientists.

Despite the deterrents to entering the Sala Pasilor(“Footprint Room”) in Ciur-Izbuc Cave, human activitysince 1965 has led to significant destruction of theancient footprints, and in the summer of 2012, weattempted to document and preserve them to the extentthat we could. We also tried to reconstruct Riscutia andRiscutia’s (1970) data and results, but with limited suc-cess. The behavior of the ancient humans was

Grant sponsor: Kutztown University, USA; Grant sponsor:National Research Council, Romania (CNCS-UEFISCDI GrantIDEI 31/2010 [KARSTHIVES Project]).

*Correspondence to: David Webb, Department of Anthropology,Kutztown University, Kutztown, PA 19530.E-mail: webb@kutztown.edu

Received 2 April 2014; accepted 17 June 2014

DOI: 10.1002/ajpa.22561Published online 00 Month 2014 in Wiley Online Library

(wileyonlinelibrary.com).

� 2014 WILEY PERIODICALS, INC.

AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 00:00–00 (2014)

investigated in part by continuing with the researchplanned by Riscutia and Riscutia (1970). Specifically, amap of the cave was produced, on which the survivingfootprints and metal flags were plotted. This allowed thereconstruction of some aspects of the movement of theancient printmakers.

MATERIALS AND METHODS

Site

Ciur-Izbuc Cave (N 46�5101000, E 22�2400000) is locatedin the Western Carpathians (Romania) (Fig. 1). It wascarved into Middle Jurassic limestone at 395 m abovesea-level on two levels; an upper, 605 m-long, hydrauli-cally inactive level and another lower one, 425-m long,which is temporarily active (Moldovan et al., 2012).

The entrance to Ciur-Izbuc Cave is at the re-emergence of a subterranean stream and it is locatedonly about 0.5 km southeast of the presumed earlierentrance used by the ancient footprint makers (Fig. 1).The old entrance is now clogged by a massive debriscone and flowstone suggesting that it collapsed thou-sands of years ago. The Sala Pasilor is now accessibleonly after 20 min of hiking and creeping on hands andknees from the downstream, gated entrance.

Along the subterranean stream, the sediments aremainly composed of gravels and sands in the downstreamsection. In the upstream section and in the upper levelthey become finer, that is, silt- or clay-sized. The entirefloor of the Sala Pasilor section is covered by a red claylayer apparently the result of a major flooding. Bothwithin and above the clay layer fossil bones of Ursus spe-laeus (U. spelaeus) are apparent and in the remote partof the chamber several hibernation nests were recorded.No excavations have been carried out so far, but observa-tions in several natural outcrops suggest that fossilremains are abundant below the clay layer. It appearsthat the clay layer was deposited in the upper level of thecave when a massive water inflow in the lower passagecreated a reservoir behind the constricted passages down-stream. Initially, the coarser sediments were transporteddownstream in the lower level. However, in the upper

level which was filled only by water backing up into itfrom below, the fine clay was decanted on the floor of theupper passages. As the water flow returned to normalrates in the lower passages, the upper passages wereslowly drained, leaving the clay on the floor.

Currently, the clay surface also shows desiccationcracks and it is slightly hardened which, considering thecave’s microclimate conditions, hints at a pre-Holoceneage. In addition, numerous stalagmites grew in many pla-ces atop the clay layer attesting to its age. The footprintswere probably made very shortly after the deposition ofthe uppermost several centimeters of the sediments, sincethere is virtually no material between the last fluviallayer and the footprints. Subsequently, a thin (�1 mm inmost areas) layer of white calcitic dust has covered thefootprint layer. This layer can accumulate during longperiods and is considered to be a result of the condensa-tion corrosion of the limestone from the walls and ceilingof the cave. In addition, bat feces has now filled portionsof a few footprints.

Footprints

To document and preserve the human footprints, eachprint that was still visible was photographed (Fig. 2)with a measuring scale and magnetic compass. This wasto allow the measurement of linear dimensions and ori-entation at a later date. A total of 51 footprints werephotographed. To explore the possibility of making casts,one footprint of a dog or wolf was cast with modern den-tal casting stone. The resulting cast was good, but thesubstrate was too fragile and the entire print wasdestroyed. Therefore, no human prints were cast.

Where possible, all footprints were also measured insitu for maximum length, ball width and heel width.Maximum length was measured parallel to the longitudi-nal axis of the footprint, while ball width and heel widthwere measured perpendicular to the axis. The longitudi-nal axis was determined by eye on the basis of the tech-nique of Webb et al. (2006a, b), which was very similar tothe technique that Riscutia and Riscutia (1970) used. Intotal, 51 human footprints were measured, though not allmeasurements were possible for every print.

TABLE 1. Original measurements of footprints from Ciur-Izbuc Cave.a

Dimension Range Average Dimensions of Cast Variance Standard Deviation Coefficient of Variability Average Error

Dimensions (in mm) of the large prints and the plaster cast (of the man)

1 Pte-Ap 260-320 278.98 280 24.44 4.9 1.77% 0.752 Mtm-Mtl 100-130 109.29 115 21.43 4.6 4.21% 0.683 Crucial Index 34.53-45 36.48 41 4.78 2.1 5.7% 0.344 Plantar Body 220-260 230 232 9.19 3.03 1.32% 0.495 Heel 60-80 69.25 69 26.27 5.12 7.38% 0.82

Dimensions (in mm) of the middle-sized prints (of the woman)

1 Pte-Ap 220-260 243.63 -- 72.7 8.52 3.4% 1.152 Mtm-Mtl 70-120 95.72 -- 188.3 13.7 14.2% 1.93 Crucial Index 31.81-48 38.44 -- 13.54 3.67 9.17% 0.584 Plantar Body 180-225 196.77 -- 151 12.25 6.22% 1.785 Heel 50-80 65.3 -- 61.50 7.84 12.02% 1.12

Dimensions (in mm) of the small prints and the cast (of the child)

1 Pte-Ap 170-220 198.54 200 56.25 7.5 3.77% 1.092 Mtm-Mtl 70-100 85.82 94.0 105.8 10.2 11.88% 1.573 Crucial Index 21.17-50 42.71 47.0 37.48 6.12 14.32% 0.974 Plantar Body 140-170 161.79 154.0 78.46 8.85 5.47% 1.275 Heel 50-70 55.91 50.0 31.81 5.55 9.93% 0.84

a Translated and reformatted from Riscutia and Riscutia (1970).

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The lengths of the footprints were used to estimatethe minimum number of individuals (MNI) who leftthem. Standard deviations of footprint lengths werecalculated for seven modern subjects who made foot-prints in a sand volleyball court. For one trail, thesand was left in a moderately packed state, and for asecond trail, the sand was loosened with a rake. Thiswas intended to approximate the variety of substrateconditions found in Ciur-Izbuc Cave where the floorwas, in some places, dry and moderately firm and, inother places, wet and muddy. When seven modern sub-jects, aged from 2 to 52 years, made a total of 314 foot-prints in both loose and packed sand, the total rangeof footprint lengths was 122–298 mm (Table 2). If, weuse the average standard deviation of the modern sub-jects’ footprint lengths (6.67 mm), we can estimate a95% confidence interval for the range of lengths forone individual.

The average standard deviation, multiplied by 1.96and doubled (for two tails), gives us a range of 26.14 mmfor the 95% confidence interval. If this range of footprintlengths can be used as an indicator of how much varia-tion can reasonably be expected among the prints of oneindividual, then we can divide the total range of the

Riscutias’ data by the 95% CI for one individual, to esti-mate the MNI necessary to make the original set of foot-prints at Ciur-Izbuc Cave.

Footprint length was also used to estimate the rangeof statures of the individuals. Using the regression equa-tion of Tuttle et al. (1990), the stature range of eachputative individual (according to Riscutia and Riscutia,1970) was estimated. Stature was also estimated using15.5% as the proportion of stature made up by the foot-prints. This value was based on the seven modern sub-jects’ footprints and stature. A range of statures wascalculated for the entire set of footprints reported by theoriginal team.

A map of the cave was produced by two of us (BT andIN) using modern surveying equipment and each surviv-ing footprint and each metal flag, even without an asso-ciated print, was plotted on the new map. This allowedthe reconstruction of some aspects of the movement ofthe ancient printmakers, including their general pathsand the extent of their incursions into the cave. Theminimal time for their movement within Ciur Cave wasalso estimated, based on the number of footprints notedby Riscutia and Riscutia (1970) and the distancescovered.

Fig. 1. (a) Location of Ciur-Izbuc Cave in north-western Romania (star); (b) plan of Ciur-Izbuc Cave (1:500 scale) with locationof the footprints in the Sala Pasilor (top right) and the former entrance to the cave (X); (c) profile of the cave in east-west orienta-tion (c).

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AMS 14C dating

To refine our estimate of the age of the footprint layerat Ciur-Izbuc Cave, two U. spelaeus bone samples wereradiocarbon dated at the Poznan Radiocarbon Labora-tory (Poland). The U. spelaeus bone samples, taken at adepth of only 2 cm below the footprint surface, wereapproximately coeval with the footprints, consideringthe quick deposition of the waterborne sediments on thefloor of the cave, in the Sala Pasilor section.

For the AMS 14C dating, the collagen extraction wasperformed using the method described by Pietrowskaand Goslar (2002) and the extracted collagen was thenpurified on Elkay 8 mm filters, and ultrafiltered onVivaspin 15 MWCO 30 kD filters (Ramsey et al.,2004). Content of 14C in the samples was measuredfollowing the protocol described by Goslar et al.(2004). A preliminary step included a check for colla-gen degradation by measuring %C and %N in wholebone using a Flash EA1112 Series analyzer (ThermoScientific). The samples are regarded as suitable forcollagen dating, if the nitrogen content in bone is notlower than 1%.

RESULTS

MNI

The range of lengths obtained by us (157–318 mm) issimilar to the Riscutias’ range (170–320 mm). However,among the measurable prints, there are no clear divi-sions according to size or morphology.

The total range of footprint lengths, based onRiscutia and Riscutia’s (1970) data, suggests that more

than three individuals left the footprints at Ciur-IzbucCave. Their reported range was 170–320 mm. If theaverage standard deviation of the seven modern sub-jects is a good indication of the variability of footprintlengths, we can use the following formula to estimatethe MNI represented by Riscutia and Riscutia’s (1970)data:

range of lengthsð Þ= s:d:ð Þ 1:96ð Þ 2ð Þ5MNI

320–170mmð Þ= 6:67mmð Þ 1:96ð Þ 2ð Þ55:74 � 6MNI

Using our own measurements of footprint length, weobtained a wider range (157–318 mm) and, therefore:

318–157ð Þ= 6:67mmð Þ 1:96ð Þ 2ð Þ56:16 � 7MNI

Stature

The stature of the Ciur-Izbuc Cave individuals wasestimated in two ways: with a regression formula and bythe percentage of stature represented by the foot. ForRiscutia and Riscutia’s (1970) three purported individu-als, the stature estimates are given in Table 3.

Based on our own measurements (Table 4), a totalstature range of 1.064–2.140 m was estimated using Tut-tle et al.’s (1990) regression equation (stature 5 6.73 3print length 1 0.007; r2 5 0.786), where both stature andprint length should be in meters.

Movement within the cave

Figure 4 shows a map of part of the Sala Pasilor withthe footprints in small, blue numbers. For those foot-prints that were still visible, a marker showing side anddirection was placed at the appropriate point on themap. From this information, it is clear that some areasof the cave were walked on more than once and in sev-eral directions. Many footprints appear to show move-ment along curvilinear paths, suggesting the paths thatwere followed by the ancient visitors to Ciur-Izbuc Cave.The total geographical distribution of the footprints isabout 75 m, from northeast to southwest and all arewithin the section of the cave called the Sala Pasilor.

Radiocarbon dating

The results of radiocarbon datings are given in Table 5.The results are virtually identical within the analyticalerrors. All ages were calibrated using the OxCal 4.2.3program (Ramsey, 2009) and the IntCal 13 calibrationcurve (Reimer et al., 2013). The calibrated ages corre-spond to a relatively wide time range (�35.5–37.8 ka).However, the median calibrated ages are consistent andindicate a maximum theoretical age of �36.5 ka cal BP.Two other attempts were made to date bone fragments

Fig. 2. Photograph of one of the best-preserved footprints inCiur-Izbuc Cave. (To activate the interactive 3-D mode, viewPDF in Adobe Reader and click on the image plate.)

TABLE 2. Descriptive statistics of modern subjects

Subject Age Sex Stature (m) Mean ft. len Std. Dev. Ft len/stat (%) Count Range (mm)

CI01 51 M 180.3 28.500 0.595 15.8 29 27.5–29.5CI02 52 F 167.6 26.100 0.672 15.6 53 24.8–27.5CI03 19 F 167.6 24.903 0.765 14.9 62 23.4–26.5CI04 2.5 F 86.4 13.691 0.541 15.8 53 12.2–14.8CI05 14 F 180.3 27.220 0.542 15.1 25 25.9–28.3CI06 19 F 175.3 26.356 0.834 15.0 52 24.5–27.9CI07 21 M 177.8 28.460 0.722 16.0 40 26.8–29.8Mean 25.5 – 162.2 25.03 0.667 15.5 44.86 –

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taken from the surface but both failed due to insufficientcollagen preservation—a common issue for fossil remainsof this age found in caves.

DISCUSSION

People

Using Riscutia and Riscutia’s (1970) range of footprintlengths produced a very large range which, in turn, sug-gested six or seven individuals, instead of the three indi-viduals that Riscutia and Riscutia postulated. It isworth noting that only one print (#139) was �300-mmlong. Riscutia and Riscutia measured it at 320 mm andwe agreed with them (318 mm). It is an enormous foot-print, being �30 mm longer than the next largest print(two other footprints measured 290 mm.) It is thereforepossible that the individual slipped while making print#139, elongating the footprint and misleading bothgroups of scientists. In addition, the maximum staturewould be only 1.959 m (60 500) by regression, or 1.883 m(60 200) by percentage. Whether or not there was a mis-take in interpreting print #139, there must have been atleast one very tall individual, probably an adult male. Inaddition, the shortest individual probably was a child.Several footprints that are still measurable agree withRiscutia and Riscutia’s (1970) results in being below180-mm long. By either technique, these smallest printswould represent an individual below 1.2 m (4 feet) tall.

As shown by Wunderlich and Cavanaugh (2001), thereare no significant shape differences between male andfemale feet that would show in the footprint (one possi-ble exception is the length from the heel to the lateral

ball, which differed by only 0.82%, or 1.43 mm, and istherefore not very useful in determining sex from foot-prints). Therefore, it is not possible to determine the sexof any of the printmakers at Ciur-Izbuc Cave, except onthe basis of size. It is unlikely that a woman would beas tall as our estimate of the tallest individual (at least1.883 m), so there was probably at least one adult malein the group.

Duration of incursion

If the group of ancient printmakers covered a distanceof 75 m twice (once on the way into the cave and onceon the way out), it would not have required more than afew minutes to do so. To walk from one end of the foot-print distribution to the other and back again wouldcover about 150 m. At a pace of 0.89m/s (2 mph), itwould take approximately 3 min for one person to coverthe distance. At half that speed, 0.44 m/s (1 mph), itwould take about 5.5 min to traverse (twice) the entiredistance represented by the footprint distribution.

Another approach to the question of how long theancient footprint makers were in the cave is to accountfor the time necessary to make all the footprints thathave been discovered. Tuttle et al. (1990) reported anaverage cadence of 94.0 steps/min for their South Ameri-can subjects walking on a smooth, flat surface. Robinsonand Smidt (1981) found a cadence of 107 steps/min at aslow speed (1.12 m/s) of walking on level ground. Oberget al. (1993) reported a cadence of 94 steps/min in slowwalking subjects on a level surface. Thus, a reasonablecadence for slow walking on level, well-lighted terrain isabout 90–100 steps/min. If we assume that one personexploring a dimly lit cave with an uneven floor of vary-ing consistency moved at only half that cadence (�45steps/min), then it would take about 9 min for him tomake 400 footprints. If there were more than one per-son, it would have taken much less time to produce allthe footprints that the Riscutias’ claimed to have seen in1965. So, again we have evidence for less than 10 min ofhuman activity in Ciur-Izbuc Cave.

It is difficult to believe that such a large, spaciouscave as Ciur-Izbuc Cave, was visited by one small groupof people for fewer than 10 min many thousands of yearsago, but not entered again until 1965. However, we can-not know how long the ancient entrance was open orwhether that ancient incursion was the first one. Itseems likely that the cave entrance was open for manyyears before the time when the known footprints weremade. However, relatively rapid deposition of cave floorsediment, by flowing water, probably destroyed and/orcovered any evidence of previous human activity in thecave. With virtually no evidence of additional depositionor human activity, we can conclude that the anciententrance to Ciur-Izbuc Cave collapsed shortly after thefootprints were made. As no archaeological excavationshave been performed, it is possible that the remains of agreat deal of earlier human activity lie buried beneaththe current cave floor sediments.

TABLE 3. Stature estimation of Ciur-Izbuc Cave individuals,based on footprint lengths

IndividualPrint lengthrange (mm)

Stature byregression

Stature bypercentage

Child 170–220 1.151–1.488m(30 91=400–40 101=200)

1.097–1.419m(30 700–40 800)

Woman 220–260 1.488–1.757m(40 101=200–50 900)

1.419–1.677m(40 800–50 600)

Man 260–320 1.757–2.161m(50 900–70 100)

1.677–2.065m(50 600–60 900)

Individuals are based on size categories created by Riscutia andRiscutia (1970).

TABLE 4. Measurements of surviving footprints

Printlength

Ballwidth

Heelwidth

Minimum 157 60 40Maximum 318 105 80Average 232.34 85.96 63.44Std. dev. 41.89 12.83 10.59Count 29 25 42

TABLE 5. Radiocarbon measurements of the samples from Ciur-Izbuc Cave

Field number Lab. no.%C

(bone)%N

(bone) 14C ageCal BP

age (median)Age rangecal BP (1r)

Age rangecal BP (2r)

PC1/0-001 Poz54805 3.2 1 32,500 6 400 36,511 36,995–35,915 37,852–35,570PC1/0-005 Poz54806 4.7 1.7 32,200 6 350 36,112 36,460–35,689 37,048–35,251

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Activities

The people who left their footprints in Ciur-IzbucCave passed over some of the same points more thanonce, travelling in nearly opposite directions (Fig. 3).This and the general distribution of footprints suggestthat similar paths were followed on the way into thecave and again on the way out. As most areas of theSala Pasilor have high enough ceilings and wide enoughfloors that it was unnecessary to retrace their steps, wecan speculate that their outbound path was mostly achoice, perhaps for the sake of familiarity. One group offootprints and flags, near the eastern-most extent of thedistribution, occur in a circular pattern. Unfortunately,very few of these prints have survived to the present, soit is not possible to determine if the direction of thoseprints follows the perimeter of the circle. However, thecircular grouping of prints surrounds an area of the cavefloor that is somewhat raised above the surroundingfloor, so it is likely that this “mound” was intentionallyskirted.

In no case, do we find footprints (or hand prints) inthe areas of the cave that would necessitate crouching orcreeping on hands and knees. Furthermore, while thereare a few clear instances of slipping in the soft, wet sedi-ment, no handprints or knee prints have ever beenfound, suggesting that none of the ancient visitors fellduring their exploration of the cave. This may bebecause the ancient entrance was near enough and largeenough to admit plenty of light to the areas where thefootprints have been found. It also suggests that theancient visitors entered the cave during the day.

Dating

The ancient human footprints were first thought to beabout 10,000 years old, based on evidence of cave bears(U. spelaeus). Because there are a number of cave bearfootprints and skeletal elements, including completeskeletons, we believe that the humans who entered

Fig. 3. Map of a portion of the Sala Pasilor with directional and positional indicators of some of the surviving footprints. Ifdirection was discernible, the arrow points in the direction of movement (towards the toes); the point of the arrow represents thehallux, while the barb represents the fifth digit. Thus, left and right footprints can be distinguished. A line segment, with no arrow,represents orientation, but not direction. Where numbers occur without a line or arrow, only the metal tag was found.

Fig. 4. Photograph of print #173, apparently overprinted bya bear; (a) without lines; (b) with outlines of human and bearprints.

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Ciur-Izbuc Cave were approximately coeval with thebears. In addition, one or two human footprints (Fig. 4)were apparently overprinted by bears. Even if thehumans overprinted the bear footprints, the timebetween the deposition of the current cave floor and thecollapse of the ancient entrance was probably very short,as discussed above. Therefore, the human incursion intothe cave probably occurred before the extinction ofU. spelaeus in Eastern Europe. The youngest dated cavebears in Europe are about 27.8 ka cal BP (Pacher andStuart, 2009). This date is consistent with the youngestdates of cave bears from Ursilor Cave, Romania, only�25 km from Ciur-Izbuc Cave, which are dated at 31–29ka cal BP (Constantin et al., in press).

The two cave bear bones tested here yielded consistentages around �36.5 ka cal BP. They thus establish a ter-minus post quem for the age of the human footprints.Although we were not able to date fossil remains scat-tered on the surface of the clay layer, we have to con-sider that: 1) several cave bear hibernation nests arepreserved dug into the clay and bonebed of this passage;2) scattered cave bear remains are present on the claysurface. It appears thus that the human footprints dateback to a time later than �36.5 ka but earlier than thelast documented cave bears in the region, i.e. �29 ka calBP. Unfortunately, except through the ursine remainswe have no method of dating the footprints, since noancient artefacts have ever been found in Ciur-IzbucCave, nor has any charcoal.

CONCLUSIONS

At the time that Ciur-Izbuc Cave was visited by theancient footprint makers, Romania and the rest ofEurope were going through a transition. Paleoanthropo-logically, Neanderthals were being replaced by humans,likely with some admixture; culturally, Middle Paleo-lithic technology was being replaced by the Upper Paleo-lithic; and faunally, cave bears were nearing theirextinction.

In recent years, discoveries of early human remains orcultural agency have been made in other caves from thewestern part of Romania. In fact, some of the earliestHomo sapiens remains in Europe (ca., 35 kaBP uncali-brated) from the Pestera cu Oase (Trinkaus et al., 2003;Higham et al., 2011) were discovered only �200 km SWof Ciur-Izbuc Cave. The Coliboaia Cave, with its recentlydiscovered rock art, arguably dated to about 32,000 calBP (Clottes et al., 2012), is less than 40 km away. And,Upper Paleolithic dates from Germany indicate thathumans moved into the area by 40 ka cal BP. In addi-tion, H. sapiens remains from Woman’s Cave (PesteraMuierii) and Cioclovina Cave (Pestera CioclovinaUscat�a) were dated at about 35 and 33.5 ka cal BP,respectively (Olariu et al., 2005; Soficaru et al., 2007).These sites provide evidence that H. sapiens was estab-lished in Eastern Europe and, specifically in Romania,around the time that the footprints in Ciur-Izbuc Cavewere made. Furthermore, Pestera cu Oase is apparentlyolder than late-surviving Neanderthals in Europe (Smithet al., 1999; Trinkaus et al., 2003). Indeed, severalauthors have suggested that humans and Neanderthalsinterbred, resulting in combined morphology of earlypeoples in Europe (e.g., Trinkaus et al., 2003; Condemiet al., 2013), and leading to a small but significantgenetic legacy in modern humans of Eurasian descent(Green et al., 2010; Sankararaman et al., 2012). There-

fore, it seems that the (indirectly) dated footprints fromCiur-Izbuc Cave, which may be as old as 36.5 ka cal BP,are from a period when Neanderthals were beingreplaced by humans.

Unfortunately, dating methods and results for theregion are currently also in transition (e.g., Conard andBolus, 2003; Richter et al., 2009), making it difficult toplace the footprints at Ciur-Izbuc Cave in a precise bio-logical and cultural context. If more recently reporteddates for the transition from Neanderthals to H. sapiensare more accurate, then the footprints discussed herewere made near the end of that intermediate period, orshortly after it. They were, therefore, most likely madeby early H. sapiens in Europe or by sapiens/neandertha-lensis hybrids. Without any hominid fossils or artefac-tual evidence from Ciur-Izbuc Cave, it is impossible tosay precisely who made the footprints there. Only properexcavation of the sediments in Ciur-Izbuc Cave will tellus more about the makers of the ancient footprints (or,at least, their immediate predecessors). If H. sapiens isshown to have inhabited the cave prior to the creation ofthe footprints, then it is very likely that the prints weremade by anatomically modern humans.

ACKNOWLEDGMENTS

The authors like to thank Tom Greiner for statisticalhelp and suggestions, and Viorel Lascu, custodian of Ciur-Izbuc Cave, for access to the cave.

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